As to what your therapist did, yes I think the way she reacted was ridiculous and over the top. Was this unethical? Well frankly I think therapy is unethical at its core. I also think it's a good thing ultimately that she terminated with you, not for her benefit but for yours. She sounds like a huge baby. But of course you're hurt and that's normal. If you think it will bring you some relief to sue her, hey why not. I don't know whether you have a case since I don't know the rules in your country but I think it's always good to let therapists know they screwed up. They don't get to hear it enough imo.