It may be true that you shouldn't have told other people without asking her first, BUT that doesn't mean her reaction was necessarily right either. I think she just freaked out and overreacted because she didn't want others to know yet that she isn't straight. She may not even really know herself, or hasn't accepted it yet. Really the only advice I can think of would be to try to talk to her about it, see if there's any kind of relationship still there and who/when to tell about it.