I think my inlaws think I have bowel issues cause I spend so much time in the bathroom when I am at their house. I really just need space.
Why do you want space from them?
Because they have been rude to me on many occasions
There's nothing wrong with wanting space. You should just tell your in-laws you need space. It might be uncomfortable for them if you're always occupying the bathroom.
If they weren't rude, I wouldn't have an issue telling them
Maybe they're rude because they think your behavior is rude, but that's just a guess. I respect you wanting your space, but honesty is the best policy regardless of how they take it.