It sounds very much like she realized that she had done something unethical and that she could not deal with that.

If you live in a city, then you may have some resources to help you find some other support. Support groups, especially those run by peer support specialists, have been helpful to me. You don't have to divulge the specifics, just that you learned that your therapist had revealed information about you to another client and that you feel betrayed and don't know where to turn. Do you want to try to find another therapist? Or do you feel (understandably) somewhat hesitant to look for that?

You can also PM me if you think that will help, and certainly continue to write about your situation here. I left my last T almost a year ago and have found the support and opportunity to vent on PC to be an enormous help.

There are some other forums here, too, about specific issues -- depression, anxiety, relationships, etc. They have helped, too. Usually very friendly and supportive.

It seems unlikely that the information could be used or spread in any other way that could be damaging to you, but I definitely understand how terrifying even that possibility must feel. If you can find a way to get some support then that fear might be lessened somewhat, and you can start on a plan to find out what is the best way to make sure that it will and cannot be used against you again, if you want to do that.