Why?

Why do I feel so empty and hopeless?  I've decided to go skydiving on September 17.  My first thought was "maybe I'll get lucky and the parachute won't open" except there will be someone with me.  I just can't figure out what will make me happy and make me forget him.  He's moved on...why can't I?  He doesn't love me anymore.  Why can't I stop loving him, needing him, wanting him?  Why?  It's just not fair!