Valentine's Day is just around the corner and you know what that means: Love is in the air.

But, from a scientific perspective, what exactly is love, anyway?

While you kinda already know what love is, scientists have actually broken down love into three categories: lust, attraction and, finally, attachment. Each category has its own evolutionary advantages, and – surprisingly – involves its own set of hormones.

Each stage of love – from that initial attraction to, possibly, a painful breakup – leads to temporary chemical changes in your brain. Here's what's going on.

The evolutionary advantage of lust isn't a secret – it's to drive home humans' need to reproduce and pass on our genes to the next generation. And it's mostly controlled by sex hormones like estrogen and testosterone. While estrogen is usually called a "female" hormone and testosterone a "male" one, men and women actually have both. And it's the balance between estrogen and testosterone in both men and women affect your libido.

Now we're on to those warm fuzzy feelings you experience when you're around someone you like. Attraction involves brain hormones called dopamine, serotonin and norepinephrine. Both dopamine and serotonin are "feel-good" hormones, while norepinephrine gives you energy – which is why the sight of your significant other makes you so happy.

Dopamine is especially important in your brain's natural reward system, the same region of your brain involved in addiction. That's part of why a new relationship can feel so intense – your brain's reward system tells you to spend more and more time with your S.O., sometimes to the point that it can feel (temporarily) all-consuming.

If you're in it for the long haul, your feelings will last well beyond the "honeymoon period." Like attraction, attachment is also controlled by brain hormones like oxytocin, the "cuddle hormone" that triggers bonding with your partner.

Oxytocin is produced in your hypothalamus, a region of your brain that controls emotions. And it's designed to create long-lasting bonds (to give you an idea of how long-lasting its effects can be, oxytocin is also important for bonding mothers to their children). And because oxytocin is also important in friendship, it makes sense that someone you love also feels like your best friend.

At the same time, some regions of your brain become less active. Like your amygdala, a region of your brain responsible for feelings of fear. Studies have shown that pair bonding (that's science-ese for a long-term monogamous relationship) likely reduces overall fear levels, which helps explain why being in a secure relationship feels so comforting.

We hate to spoil the mood but, well, even some of the best relationships end at some point. And breakups have an impact on your brain function, too. As Scientific American explains, the sting of rejection you can feel after a break up trigger pain centers in your brain – and essentially mimic actual physical pain. The pleasure centers in your brain can also become (temporarily) less active, leading to brain activity that's similar to mild depression.

The good news, though, is that the effects are temporary. Within a few weeks to months, your brain rebounds – and you're ready to fall in love again.