Im fat and ugly and gross (im a teen boy please read)?

Ok I am a 15 year old boy. I look like 19 but I have had a girl say I looked 30. I am fat my weight yo yos like no other. It went from 290 to 358 down to 280 up to 360. When I'm playing football it sheds but when I'm just sitting at home it packs on. I'm trying to get back down to 280 before I start school in september. But I'm so ugly I don't think I'll ever get a girlfriend. My face has little acne scars and my cheeks are darker. I had a face fungus I guess I've pretty much cleared it up but still. I hate the way I look. What should I do? How can I get a girl? What can I do to look younger?