I've been through something similar, and I went to the university counseling center, and student advocacy. You could also try disability resources if you can get documentation from a doc (at the counseling center or hospital). Neither they nor you would have to go into detail, and I'd advise against it re: suicide. They could just say you have X diagnosis, and you're seeing them, working through it, etc., and this is how it affected school. I would say approach your professors sooner rather than later, but you don't have to be specific, just say it's a health issue and you're working on getting documentation, since you've already been seeing doctors about it. Most professors will work with you. They've accommodated students before, and they're used to having things come up. Even if they wonder if you're making excuses, I don't think they even can say that; they'll still work with you as long as you can provide documentation from a doc. And honestly, most profs don't even ask for that, they just take you at your word.