Hi! I agree that you should talk to your regular doctor about the situation. You could be a chronically depressed person. I honestly think I was during high school and through the rest of school. I finally saw a counselor and didn't take meds, but learned what was going on with me. Maybe you could talk to a school counselor. Of course, I might be totally wrong. I'm just guessing. I was also really shy. It's good to check early just in case you're a bit off track.
Being able to have energy and really enjoy life is priceless.
P.S. Welcome to Psych Central! We have lots of teens here and even have a forum and groups for you guys. You can join social groups after you get five posts accepted (printed.) Here's the link, so you can see all of our groups:
http://forums.psychcentral.com/groups/.