That makes me really sad..:(
Just know that probably all of those girls you’re thinking that about are thinking the exact same thing to some extent. Everyone is insecure about something. That’s just in our human nature. So don’t be so harsh on yourself. Just be happy with what you got and always think, it could be worse. Try reading The Secret, too :) I haven’t read it but I heard it helped a LOT of people with issues like that, and many different other things too in life.
Take care <3