am I a failure?

Hi..does anyone have advice for me? I just turned 14 and I already feel like a failure... im in a school that's considered top in my city but my grades are falling, I quit many activities and have no social life. I used to be the girl who's "pretty, has lots of friends, a topper, naturally smart and good at music and sports". But now.. I only have like 2 friends at school, im insecure, im not pretty, and i quitted orchestra and gave up other activities and posts because I don't have friends. My grades are also dropping cuz..I just don't have motivation and im depressed. I feel like the things my parents gave me, like basketball lessons, music lessons are all wasted because I don't join any sports or music activities now. Am I really a failure? My old friends from other schools join many activities, meet many people, and are enjoying their teenage life. And me? I'm sort of just..existing. Not even a topper anymore. What am I? What can I do to be better or to not feel this way? Can anyone relate :/