I feel lonely and depressed?

i couple weeks ago i told the guy i liked how i felt about him. a week later he starts going out with my worst enemy. I started to get really sad and i listen to crap that i never used to before (like goodbye secondhand serenade, i miss you jamestown story, fall for you secondhand serenade, cry james blunt, goodbye my lover james blunt) now i feel really bad and my sleeping habits have changed so im barely getting enough sleep, maybe a couple of hours each night. my science teacher is worried about me because i might have sleep deprivation and i keep looking tired all the time and she thinks it might be something with me attracting asthma or a breathing problem.