Struggling with Obesity: Seeking Advice

I've been struggling with obesity since I was a child, like there wasn't a time where my weight was ever average, i was always considered obese. I turned 18 in May and my physician recommended I talk to a specialist about getting a surgical procedure to help control my rapid weight gain. i was diagnosed with pcos when I was 17, due to my pre-diabetic status. I've tried general dieting and exercise, before my diagnosis and then the recommended diet and exercise after my diagnosis and my weight always plateaus after I loose a few pounds (like 2 or 3 pounds). I've struggled with disordered eating so calorie counting is out of the question. I weigh around 320lbs last I checked and I wouldn't be surprised if it's higher now. I desperately do not want to get any kind of surgery to aid my weightloss because I'm positive it won't work. I don't know what to do as the regular stuff doesn't work and there doesn't seem to be any of the typical underlying ailments that would cause these problems. I'm sick of being so unhealthy, but I feel there's nothing I can do.