I am always tired, no matter how much sleep I get, could it be...?!

If I were u if just go see if anything is wrong

If you get a blood test done, expect the doctor to tell you you're anemic, with low levels of iron in your blood. Without iron in your blood it inhibits the production of red blood cells or something like, which means you don't get enough oxygen around your body.

It's a common problem, if that's the case, you probably aren't getting enough iron, vitamin C (required to absorb iron) or you're drinking too much coffee or energy drinks, the caffeine sucks the iron out of your blood when it's removed.

Also if you happen to be a vegetarian, that won't help, without meat you'll need to take iron in a capsule form to supplement it.

My medical history as a teenager.

It is normal to be tired all the time during puberty. I believe that is what the doctor will tell you but if it is affecting you enough and you wish for it to stop then you should definetely see a doctor.