You may have noticed that your bathroom habits get pretty wretched right around your period.

(If not, consider yourself among the lucky few.)

The bathroom struggle is very real.

You either can’t go or can’t stop going. Or if you’re really, really unlucky… both.

And ohhh, the period farts.

So what’s going on with your digestive system that creates this hostile environment for your bowel — and, frankly, everyone around you? It mostly comes down to anatomy, hormones, and food.

First, there’s the issue of location: Your uterus is right near your colon.

Before your period, the lining in your uterus thickens to get ready for implantation. As the uterus gets more engorged, it can press up against the colon and lead to constipation and bloating, gastroenterologist Robynne Chutkan, MD, author ofGutbliss, tells BuzzFeed Life. Then, as the uterus deflates, it can make it a lot easier to go (sometimes too easy).

Hormones like to eff with your poop habits, too.

The hormone progesterone peaks right before your period, which may have an effect on how things move through your intestines, ob-gyn Alyssa Dweck, MD, coauthor of V is For Vagina tells BuzzFeed Life. “So some people will have alternating constipation or diarrhea or just a general feeling of discomfort or gastrointestinal stress.”

One study found a relationship between period poop changes and prostaglandins, the hormone-like compounds that can trigger cramps. They found higher concentrations in people who had diarrhea during their periods, so that might explain why you’re looser than normal while other people complain about not pooping since Tuesday.

And those period farts? Those can come from your hormones, too. Your gut bacteria actually changes along with your cycle, since it’s affected by your fluctuating hormone levels. As the bacterial fermentation changes, your gas changes — even if your diet stays the same, says Chutkan. So that’s why it smells like you just housed some Indian food, even though you did no such thing.

But, to be honest, your diet probably has something to do with it, too.

“A lot of this has to do with the fact that people have crazy eating habits right before their periods,” says Dweck. “Some women say they will literally just eat anything in front of them.” (WHAT? NO? WHO DOES THAT? Okay, yeah.)

It’s not a huge coincidence that dairy is something that a lot of people crave most during their periods (cheese, ice cream, more cheese) and that it also happens to give most people room-clearing gas. Instead, can we all accept the possibility that your dinner of mac and cheese followed by cookies and cream froyo could have caused those heinous period farts?

Another reason you may poop more on your period: coffee. For lots of people, their morning cup helps get things moving on a regular basis. But during your period, this can translate to opening the floodgates. Add to this the fact that you’re probably downing more coffee to try to cope with how freaking exhausted you are.

Or you might just be plagued with terrible period bowels for any number of horrible, unfair reasons.

If you already have a sensitive stomach, you probably already know it can get downright tragic on your period. For instance, one study found that women with irritable bowel syndrome (IBS) reported worse pain and bloating, more frequent poops, and rectal sensitivity (yikes) during their period week.

Or it could be endometriosis, a really painful condition where uterine tissue grows outside the uterus. The bowel is a common place for this tissue to crop up, says Chutkan. Symptoms can get worse as estrogen and progesterone levels change during your period, and it may present as more of a gastrointestinal problem than a gynecological one.

Bottom line: Some people just feel nature’s wrath harder than others for a lot of different reasons. It’s not fair, but it’s also not uncommon.

So how can you get all that shit under control (literally)?

For nightmare gas, taking probiotic supplements can help. So can eating more fermented foods, like kimchi or sauerkraut, since they can provide good bacteria to the colon, says Chutkan. Cutting back on gas-producing foods, like cruciferous vegetables and beans, can also help, she says.

If constipation is your issue, Dweck suggests upping your fiber intake and drinking tons of water. For diarrhea, opt for binding foods like starches, rice, potatoes, etc., says Chutkan. You can also try popping OTC pain relievers like ibuprofen, since research shows these can reduce the release of prostaglandins (those hormone-like compounds that are associated with cramps and diarrhea).

And seriously, keep a food diary, says Dweck. If you notice that you’re loading up on dairy, sugar, and salt right before you period, and then feeling like a bloated, gassy, loose cannon… well, there’s your answer.