Sorry to hear that. Hope you're doing better now.
Honestly, I only ever seen/heard about crazies online. In your experience, do they reveal themselves to be crazy after the relationship starts? What are some signs I should watch out for?
I'm quite fine, I'm currently with another woman and we have been together for 8 years by now and she was in a very much similar place than I was with our previous partner so we kinda licked each other wounds - we got lucky in the end.
The craziest show themselves early on, others just at the start. Watch out for "me or them" and other manipulative ways of "you wouldn't do X right?" even if logically you should. If someone truly loves you, they would never put you in a dangerous situation nor willingly put you in a bad spot socially when you have made clear that you don't want to X. No good partner will force you to do something that you don't want to do, they might try to push you which sometimes it's good, but if there's a strong denial noone should force the other even if it's done with good intentions.
If she ignores every plea, don't swallow it and think that you can fix things - always talk it out and if it doesn't work, leave.
Some crazy women (and men!) are actually good hearted but will harm you and drag you down when asking for help. Be very careful with this kind of people because it's not entirely their fault, it can eat your mental health slowly and send you down a spiral - seek professional help and don't try to "man up" and do it everything yourself when you're with these kind of people. As an example, just because your partner has a phobia of crowds, you should not allow her to deny you going out to do stuff the same that you should try to help her overcome her/his fears and if there's no improvement, seek help instead of letting your partner suffer and wound you in the process.
As pitiful as some people might be and as much as you might love them. If YOU are not healthy, you cannot help anyone. Keep your mental health first, just so you can help those in need - if there's harm coming your way, don't do it alone. If you were to fail while being alone, not only you would end up fucked up, you might in return fuck up your partner even further creating a spiral that will go out of control. The worst part of this, is that it might take years for you to notice and it might be too late when you do.
Godspeed mate.