My girlfriend's family situation stresses me out and I'm thinking of breaking up with her as a result.
Aside from her family situation are there any other reasons to break up with her?
No, every time I visit her house things just make me feel so nervous.
You could let her know you don't want her to sacrifice her relationship with her family, but you need her to know how these contentious issues with her family make you feel. Ask her if she think their behavior is toxic and whether or not she sees it ending, as it could be a deal breaker for you.
I think that the best way to handle this would be to break up with her since I can't handle her family situation.
It's unfortunate that your girlfriend's family is making you feel this way, but if you aren't feeling good in the situation then it's okay for you to end things. Your girlfriend seems to be going through a lot and your relationship ending will be difficult so make sure to be respectful and kind when ending things with her.