There are a lot things happening in a therapy session that's hard to tell from your post. If you said you have sui thoughts, that might be less of a warning sign to her than saying you don't feel you can hang on any longer and things are really bad. Again, it's hard to tell from your post how it came across. I talk about this with my therapist and she doesn't overreact at all, mainly because of how I bring it up, so this kind of reaction wouldn't bother me.

If you aren't feeling safe, it would be a good idea to make that clear to her if she isn't picking up on it.