Im ruining my life ! :( helpp pleasee?

so im 17 and im really flat chested. i lie to myself and everyone else . people think im an average small sized breast girl but in reality i dont have anything . i missed my junior prom which ive been wanting to go since forever , all because i wouldnt look like a girl in a dress. after prom everyone goes to seaside for mdw and ive always wanted to go but there goes my boobs being the reason for my dissapointment, point is i wanna live a normal life and be able to go to the beach and show my body but im always hiding it . especially in the summer when every girl is wearing tank tops and shorts . im wearing sweats and a regular shirt . oh and yeah im also kind of fat , i have a big butt nd big thighs and i hate itt !!! i hate my life and i think imm gonna just hide forever and never come out idk what imma do with myself =[[[[ oh and on top of tht . i dont even have a boyfriend , i try to stay away from guys cause i feel so ashamed of my flat chested self , idont know what to do