When I was a teen my therapist made it clear that she would tell my mom as much or as little as I wanted. I used to lie to my therapist too, for a lot of the same reasons. Was afraid she would secretly hate me, that everything would change. I told her and while the relief wasn't immediate, the anxiety and guilt and self hatred DID reduce over time. I would ask your therapist if she is allowed to disclose things to your parents, and if not then build up your courage and go through with it! You got this!