If you've ever been in love, you know there's no feeling quite like it. In the beginning, rose-tinted glasses can make your partner and your relationship look as perfect as can be. But as intensely happy as you may feel, falling in love and knowing how it all might pan out can also be distressing.

These love experiences aren't limited purely to the mental realm: They have very real bodily reactions. Depending on the relationship stage, the levels of various hormones in your body go up and down in the presence (or absence) of your loved one, not only causing this range of passionate feelings but also manifesting physically — from butterflies in your stomach to a racing heart.

Here, we spoke to four relationship therapists to figure out what exactly happens to your body in love.

Love can feel a whole lot like anxiety.

Falling in love is, for obvious reasons, very exciting — and there is a fine line between excitement and anxiety. "Not being able to eat, being preoccupied, being unsettled, nervy, jumpy, ungrounded, those can be symptoms of anxiety, but they can also be symptoms of excitement," says Sally Baker, senior therapist at Working on the Body.

Other "symptoms" you may experience when spending time with your partner include butterflies, a racing heart, and flushed skin, notes Dr. Laura Vowels, principal researcher, and therapist at sex therapy app Blueheart. "These signs appear early on and can indicate that you might fall in love with someone," she says. "This is enhanced if you are physically and sexually attracted to them."

When you're apart from your partner, those intermingling feelings of anxiety and excitement can become even more pronounced. "You might find yourself preoccupied with the person's thoughts, not needing as much sleep, or forgetting to eat," Dr. Vowels says. "It's also worth noting that everyone can experience this, but people who tend to have a more avoidant attachment style (i.e. they fear intimacy and connection and tend to place a high value on independence) may not let themselves feel it quite so much."

So, what's happening in your body when you experience these anxiety-like effects of love? "A sudden rise in dopamine (which causes feelings of exhilaration and anxiety) and an associated increase in cortisol and norepinephrine (the two main stress hormones) causes a sharp drop in serotonin (a mood stabilizer)," says Clair Burley, Ph.D., a UK-based clinical psychologist. "It is also thought to explain why we become obsessed with thoughts of our new love. This drop in serotonin matches the levels of those with obsessive-compulsive disorder."

These anxious reactions are usually nothing to worry about unless they turn into anxious thought patterns where you're constantly worried about the relationship turning sour, even without evidence. "If you had, in the past, relationships that have gone wrong, or you've had unresolved heartache from previous relationships, you might switch from being excited to going into anxiety because you're being triggered," Baker explains.

On a physical level, if your constant thoughts about your loved one cause more extreme reactions, "such as heart palpitations or rapid breathing," you should pay close attention, says Tony Ortega, Ph.D., a New York-based clinical psychologist. You may be able to talk yourself down by concentrating on what's going well in the relationship, but if it keeps happening, it could cause concern. In both cases, you may need to unpack your unresolved sadness or trauma with the help of a therapist so that you can move forward with the relationship from a more grounded place.

Love is addictive.

"Your love is my drug," sang Ke$ha in 2010. And even though she called it a "stupid and fun" track, the pop star really was onto something. "The main hormone involved in both falling in love and being on drugs is dopamine," Dr. Burley says. "This hormone gives us a sense of pleasure and euphoria. Drugs such as alcohol, nicotine, amphetamines, cocaine, and heroin increase dopamine levels in our brains."

Essentially, falling in love affects our brains and bodies, comparable to the experience of addiction (although it's not quite simple). "The physical symptoms can be similar: preoccupation with thoughts of them, euphoria when with the person, and withdrawal symptoms when not around them," Dr. Vowels says. But, she adds, there's a very important distinction to make between love and substance addiction: "These symptoms, however, dissipate over time and rarely last beyond a 'honeymoon period.'"

Love can also feel like jet lag, according to Baker. "It can make you feel a bit disassociated from the mundane life," she says. On the other hand, "you might also feel a sense of hyper-clarity like you're in the zone, omnipotent, blessed." Your pupils might dilate, and even the scent of your loved one might bring you into a "higher state."

All of this may sound kind of scary — and it can be — but, in most cases, a love "addiction" is really just about pleasurable sensations, which make us want to spend more time with our partner and create a bond with them. "The rise in dopamine can also create other physiological experiences — like butterflies in our stomach, feelings of excitement, and inability to stop smiling," Dr. Burley says. "Smiling can set up a feedback loop — the happier we feel, the more we smile, and the more we smile, the happier we feel!"

And it can also cause withdrawal symptoms.

When an experience causes our dopamine levels to spike, we naturally crave more of that experience. "When someone is abusing drugs, they need more of the drug to get and maintain their high," Dr. Ortega says. "Being in love often triggers this as well, needing more of it to stay in that feeling."

When you're falling in love, you can expect to feel a certain amount of withdrawal when you're apart from your partner, so it's usually not a cause for concern. "The one feature we need to consider to distinguish if it is healthy or unhealthy is to assess the degree to which this symptom is interfering with your day-to-day functioning," Dr. Ortega explains. "For example, constantly thinking about your loved one interfering with your ability to concentrate at work could be considered unhealthy."

In the early days of a relationship, spending time apart from the person you love can trigger an "attachment panic," says Dr. Burley. Remember the feeling you got when you were separated from a parent in the supermarket as a child and thought they'd left you there? Yep, the same thing happens to your body when you're away from your partner. "This causes us stress, which we can experience as a drop in energy or an increase in worrying, headaches, upset stomach, tension in our muscles, chest pain, increased heart rate, insomnia, lowered immune system," Dr. Burley adds.

You'll often feel like you want to spend every second with your partner, but this obviously isn't practical — and that time apart can feel really lonely. "Being separated from our loved one can trigger the same part of the brain as is activated when in physical pain," Dr. Burley says. "This raises blood pressure, where the likelihood of experiencing a heart attack or stroke doubles."

But the more the relationship progresses, the more love becomes a calming presence.

As anxiety-inducing as the early stages of the relationship can be, eventually, all of these fairly extreme symptoms begin to fade. Once the relationship is more established, you're left with a sense of calm, ease, and security. Your heartbeat will slow, and you'll feel generally more relaxed around your partner.

At this stage, you've shifted into more companionate love than passionate love. "Companionate love involves feelings of mutual respect, trust, and affection, while passionate love involves intense feelings and sexual attraction," Dr. Vowels says. "Most relationships will have some combination of both companionate and passionate love."

The hormone at play here is oxytocin. "This is the feel-good hormone — it gives us that warm fuzzy feeling," Dr. Burley says. "When we hold hands with someone we love, we are not only less affected by feelings of stress, but we are also protected from feeling physical pain. This effect is strongest when we would rate our relationship as happy."

The bottom line is that you shouldn't let the potential for some really confusing feelings and sensations deter you from letting yourself fall hard for someone. Because while "love can be scary for some people depending on their past experiences," according to Dr . Vowels, "for most people actually being in love is a nice, warm feeling."