I want to kill myself, i hate everything?

everything in my life goes so completely wrong, i try my very best at making people happy but all i get from the world is it thrown back in my face! all of my friends have changed to drinking and smoking and i don't want to do that, my other friends who haven't changed to that are either really bitchy to me, or plan things without me all the time, i try my very best at something and there is always someone in my class better than me, ive been playing piano since i was 9, im now 14 and its the only thing im good at, in first year and second year loads of people gave me attention because i was quite good, then in third year, a girl just started playing the piano for a month was way better than me, so now every time i come home from school all i do is practice songs but i fail and i cant learn them as fast as she can, i have no talent and im getting fat and im ugly, every boyfriend i've had has either dumped me or hardly paid any attention what so ever, my mum and dad are constantly on my back about school, i don't do well in school no matter how hard i try, whenever something good happens to me, its over in seconds and then a really really bad thing follows it, im sick and tired of trying then failing all over again and i just want to kill my self so much.