The thing is, she's been suicidal before. Tried and failed, ended up in a psych ward. I figured that would be the type of person that understood.
Does she know you're suicidal?
It sounds like she might be dealing with her own feelings around it (e.g. guilt for loved ones who might have been upset), and is projecting them onto you/the idea of suicidal people. She might not have really dealt with the things that brought her to that point. Or she could be thinking of suicide again, and is angry, guilty, etc., and shutting down like that is her way of coping.
Either way, it puts you in a shit position. It makes sense that you wouldn't want to speak with her about the matter - i wouldn't either. I would be curious of what she would say if she realized you were suicidal (assuming she didnt know whem the two of you spoke). Maybe she would be more empathetic--or maybe not. I dont know her. Maybe youre better off talking to someone else.
I'm sorry she gave you such a shit response, and isolated you, though.