Oh honey, this is everyone else's fuck up. Your mother is a piece of work, I can't even begin to unpack that atrocity of a parent. But your therapist?! What the ever living fuck. I would seriously consider making a formal complaint. It doesn't sound like you were given a heads up or asked for consent and you were coerced into physical contact with a person who subjected you to abuse and actively protected the abuser she was fully aware of. That's so incredibly messed up and wildly unprofessional. I'm so sorry this happened to you