How am I supposed to feel?

Was watching Bend it like Beckham at school today (do not know why??)
Bloody hell that chick is skinny !

How ??
I mean I look and overall I don't think her body is the most attractive ! But god how the hell does she get that tummy????
Really?

I just feel quite big and disgusting I really regret having chocolate for my snack and I know I haven't gone up in weight and probably need more food than normal (but i do cut out bits normally anyway so lets start by putting them back in ! :/ but its hard ! )