@Lorelei,
Sleeping pills are generally not a good idea. Even if they have been prescribed for you (and I bet these haven't), they need to be carefully taken.
You sound as if some things are obsessing you, and perhaps you are under stress. I second the idea of going to your school's counselor.
In the meantime, you can also work on fatiguing yourself during the day, which includes getting physical exercise, although no later than about one hour before bedtime. Turn off electronic devices, too, and that means the phone, the TV, everything. Keep your bedroom dark and at a comfortable temperature, and set your morning alarm. Try to get to bed at more or less the same hour, too, and stop drinking caffeinated drinks (soda, tea, or coffee), or eating chocolate (also a stimulant) more than four hours before bed.