The first order of business is to schedule a quick doctor's appointment, just to make sure that you don't have an underlying condition that's making you tired, like mononucleosis. Once they rule out anything physical, you can start taking a look at whether your schedule is to blame. Turns out, Kathy, you're far from the only tired teen out there! There's a lack-of-sleep epidemic among young adults, who should be getting about nine hours a night. However, according to a recent survey by the National Sleep Foundation (NSF), only about 20% of you get that much on a school night. Not only can getting too few z's make you feel low and lethargic, but it can also impact your moods, cause you to eat more, and affect your schoolwork, driving skills, and more.

You should start by scaling back your schedule so that you're not running yourself ragged. That aside, though, it sounds like your biggest problem is that you sometimes go to bed late and then sleep in. That gets your body clock all out of whack and impacts the quality of your sleep. In fact, the NSF suggests that you maintain a consistent bedtime and wake-up time, even on weekends, which, along with getting those nine hours a night, should help you immensely. Also, make sure that you're treating your sleep time as precious: Set up a relaxing bedtime routine; don't fall asleep with the TV, radio and computer on or you'll feel wired instead of tired; make sure your bedroom is dark and quiet; and avoid caffeine after lunchtime. You may also want to do some gentle physical activity when you get home from school, even if it's just a quick walk around the block with your dog, to help perk you up. And, of course, make sure you're eating enough and snacking regularly, too, because hunger can make you feel exhausted.

Good luck and sleep tight.

—Andrea Pyros