Three weeks ago l started to weight lift.l lift for about 1-2 hours a day have school for about 7 hours, and get about 7-10 hours of sleep daily.

maybe your iron is low try taking a multi vitamin daily that will help you.good luck.

Maybe you're just stressed out, or you're wearing yourself out. cut back on the weight lifting, maybe down to an hour and a half.. see if that helps.

uau!
you're so tired because u do many thing every day, you've to do less things.

This is pretty obvious overexertion. You should not lift weights for 1-2 hours each day, especially when u just started. Your muscles _must_ rest to heal & repair themselves, & to grow & build mass.

You should work each muscle group intensively 1-2 times a week at most, & rest 2-3 days in between the workout of that muscle group. If u must work out each day u should be working out a different muscle group each day while ur others rest.

For example: Chest & arms on Mon. Lower body on Tues. Abs & back on Wed. Chest & Arms would be fine to work out again on Thurs. for instance. Make ur own routine but stick to no more than 2 workouts per week on a single muscle group.