Why am i so insecure?( no rude answers please)?

So i am 16 and a senior in highschool and i do have a boyfriend. Im not skinny but im not fat either. People tell me that i am gorgeous all the time, including my boyfriend. But i have a lot of problems regarding my self-esteem. It is so bad that i compare my self to EVERYONE. i can't even get through a whole movie without breaking down.