PLEASE HELP!

I’m a 15 year old girl, so I feel like high school is the prime time that everyone is expected to look like ‘barbie doll standard’ but I’m not.

I understand I shouldn’t lose weight just to try and fit with social norms, but I’m embarrassed by my stomach.

To put it harshly, it looks like I’m 5 months pregnant. I have no idea why, is it slow metabolism? Is it just fat and I need to exercise more or eat better (I think I do this already though, not any less than my friends who have flat stomachs)?

I JUST REALLY NEED HELP it sticks out and I hate wearing bikinis because of it, so I’m the only one wearing a one piece, but then obviously even in that it still sticks out.

Any suggestions welcome, thanks in advance xx