I hope you're still lurking, B. That way I can tell you this:
I have been through something similar to this before. I was in a social work class at the university with the same girl that I had been in a DBT group with and been at the crisis unit at the same time with a number of times. She has since gone blind, so she could not recognize me.
We were discussing qualities that a good social worker should have and she said something like "oh this is stupid, but we should address other people respectfully, like Mr. So-and-So or Mrs. Whatever." I chimed in and said that I hope she, H, did not take offense to what I was going to say because we had known each other for years. She turned in my direction, wrinkled her nose, and asked who I was. I told her my name, my last name, and she made no indication that she recognized me. So I prompted her: "You know, R, from the group. DBT." I took the chance that no undergraduate-level social work students would know what DBT stands for.
Apparently that was a mistake. She immediately flipped out-- "How dare you say something like that! You are completely out of line and have totally violated my privacy! You are totally out of line!" I apologized three times and had she made any indication that she recognized me, I would not have prompted her with DBT. Apparently I "outed" her as well as myself. She was furious. Livid. Outraged.
I was then invited to have a meeting with the professors of the social work program about the incident in class. They thought that I had violated her confidentiality but it was my defense that I could not identify myself to her any other way. At least I didn't say "oh, she was at the crisis unit with me several times" but what wound up happening was that I left the program. My excuse was that my financial aid was so messed up that I couldn't get it in time for making the first tuition payment, but the real reason was that I found H to be such a foul person that she had completely screwed up my chances to be successful in social work program. I felt very "dis-invited" by the professors, who were going to keep a "watch" over me to make sure nothing like that happened again, and if it did, I would be formally asked to leave the program. So on the first day, I started out with a black mark on my record. And I resent H to this day for it.
As happenstance would have it, I moved into an apartment across the hallway from her not much later than that.
She moved out.
I won. I chased her away. I think she is scum of the earth, but other than avoid her (and this state is like one giant small town -- anyone can be found anywhere at any place) there is nothing I can do.
I'm sorry you have to go through this Bonnie.
Love you.
We must be the change we wish to see in the world. -- Mahatma Ghandi