I'm always tired. School and stress all factor in to it.
I saw a show on tv that was all about the teenage brain, where it is in its development and how it affects our bodies, and they said that a teenager is programmed differently than children and adults. Our internal clocks are different. By nature we want to go to sleep later, and get up later. That's just how mother nature slapped us together. So it's normal for teenagers to have slight cases of insomnia and even narcolepsy since we have to get up early for school, yet still can't fall asleep until late at night 8O
Of course everyones different, so this might not hold true to everyone, but i know that's how it is for me. I get up at 5:30 every morning and usually go to sleep around 11, but dont' fall asleep until later. I usually don't work naps in because i have to do something after school, but i sleep alot on weekends.