At your height, I reckon you're not fat. You sound like a statuesque Amazon, and I'm disappointed that instead of being impressed by your physique, the children at school teased you.
You're not being a pain by saying that what I am saying sounds right but doesn't work. I hope I didn't sound flippant suggesting you try to cheer yourself up by reminding yourself of your positive qualities. Sometimes that can work, but when you're feeling horrid, you just can't believe anything valuable about yourself at all, even if it's obvious to everybody else that you have marvelous qualities. I understand how you're feeling.
It's understandable for you to want to be different, for example, slimmer, but I disagree that you're lazy because you haven't lost weight. It's hard to do - easy to decide that you want to do, but not necessarily easy to do. You're being way too harsh on yourself.
Regarding being great at something - call me silly, but I believe that everybody has something that they excell at .. it's just a matter of finding out what that is, and that can be time consuming and difficult to discover.
Lilac, you're not hogging the forum at all, you're not a burden, and you're certainly not wasting my time.
I know how it feels to be stuck in a negative cycle - it's no fun, that's for sure.