Arghhhhhh someone get me advice please!?

i've had my life on hold until i lost weight.,, ( thats ben about 3 years) im 17. I'm a top grammar school and just get annoyed at myself seeing and hearing about all the good things my peers have achieved. I'm ok at sports, ok at drama, ok at singing,ok looking, ok at making friends, ok about confidence, ok abut my grades, OK AT EVERYTHING! and bad at quite a few,,,,and don't say i must have some Special qualities because i don't, the few things that i have done, my PERFECT and excellent and everything brother, has done. no-one ever recognizes my good qualities,i keep changing my mind about what uni dgree i want to do., i have low self esteem and i am an emotional WRECK. ....I just need some constructive advice to get me started