There’s a reason you suddenly feel weird after sex, and it’s called ‘sudden repulsion syndrome’

You've sworn off Xanax and Ambien, neither of you were wildly fucked up, and for a first-time shag things went exceptionally well (considering it takes time to understand a new person's rhythm).

So why do you feel so grossed out?

Every time you've heard his name since, or scrolled past it on Instagram, you've been overcome by a wave of nausea, and not only do you never want to see him again, but you literally can't remember what you ever saw in him to begin with.

That's the Sudden Repulsion Syndrome, or SRS, speaking.

According to Dr. Jenn Mann, psychotherapist, we experience SRS because the beginning of dating is often attraction based, but once we've slept with someone, we can go from being completely enamored with them to totally disgusted in what feels like an instant. "When it happens to you, it's pretty horrific on either side," she says.

Some people think we experience SRS for myriad reasons — we saw them wearing something, or texting someone, and subconsciously it turned us off. Others blame it on the way they chew to the way their ex looks, but like everything else in this world, we know it comes down to one thing: Sex.

There are a few things that can trigger it: SRS is related to sex in general, but the biggest one is having sex too early in your situationship.

“I figured out a while ago that if I sleep with someone too soon, I never form the right kind of bond with them,” one Reddit user said. “I have to decide for sure I like them before making that connection.”

It's the same reason we hook up randomly with greasy, unemployed guys we meet at bars (and then never speak to them again), but when we meet someone we really, really like, we make them wait for it.

Think back through everyone you've ever slept with — you probably fucked the lame ones way sooner than you fucked the successful ones.

And after you did, a flood of shame probably washed over you, making you second guess what you'd done. Did I actually like him? Did I just want to get with him because I knew other people wanted to get with him? What if our friends find out?

"This feeling of being turned off or revolted by the other person is just a defense mechanism," Mann says, explaining that those feelings are legitimate and should be paid attention to. Because if your body had listened to your mind from the start, you could have saved yourself a lot of time.

You never had to second guess it at all; you knew he wasn't right from the start. The nausea is just your body's way of catching up.

Related stories recommended by this writer:

● Every guy you'll hook up with before immediately regretting it

● We asked for people to tell us about the absolute worst one night stand they've ever had and now we kind of regret it

● How to initiate a hook up with that guy you've been eyeing because you deserve to get some

@carolinephinney