Stomach fat

I'm now 18 and since 16 I've gained 50 lbs plus or minus a few. I've always carried my weight primarily in my stomach and I'm just so tired of it. I have a hypo thyroid and PCOS and I know that can effect weight gain but I always lose my determination and lately I've felt really depressed about it, I never feel sexy or good enough and I'm always hearing something from my family about how I need to lose weight. At the start of high school I was a size 3 shorts and now I'm a size 13. My hips have always been bigger than my butt and I need help finding motivation/ a workout plan that I can keep up with and that will do what I need. I'm moving away to college soon and I want to feel confident. I feel like I've tried everything...