I'm very depressed how do I get over it?

Well basically I fell head over heels for this lad who was two years older than me. He messed me about but I just don't think he cares anymore. He left school today so i won't see him again pro-bally. He did used to like me.This is the first person i've fell for and now i'm grounded for a year.. I'm very down depressed and i just cry and everything which is really weird because i used to be happy all the time and never cry...how do i get over this? I cannot keep myself busy because i'm grounded and have nothing to do..its all seems pointless i just sit and cry and listen to sad music fall asleep for the whole weekend then get up and go to school and everyone thinks i'm happy..i feel alone. What should i do? Can i do anything? Will i ever be happy again?