i dont know what GP means, but i assume it’s a sort of mental health professional? if it is, then this is medical abuse. @nevertrustadoctorwho has a lot of examples of such behaviours, if you want to feel less lonely? anyway, it was wrong of them to say this. you really do have a serious issue.
can you try to meet with another therapist? i would reccomend to at least check out a crisis line.
does anyone else have advices? i will admit i dont know enough to help you as much as you deserve