Uncontrollable weight gain

How the hell do i feel ok about uncontrollable weight gain? My doctors insist that i havent got PCOS but im being checked for endometriosis and other conditions. Unfortunately, my weight gain is uncontrollable... i try to exercise as much as possible despite being in chronic pain and heres all the diets ive been on:

Regular healthy eating

Slimming world

Ketogenic diet

Rad diet

PCOS diet

Vegetarian

Pescatarian

Vegan

I have even suffered with atypical anorexia. The only reason it was atypical was because i was thinking and behaving like i was anorexic but my body was not losing the weight it should. I was doing that for about two years and i only lost 11lbs. I was only on 300-600kcals a day.

Ive only just turned 17.

I honestly feel powerless. It cant be controlled so how can i feel ok with becoming obese as im already overweight and i just cant do anything about it anymore.