I'm really tired? (15 yrs old)?

lol!! hate to say it, but it sounds like you're overloading, plus you sound from your question like youre still pretty young so try cutting out some of the stuff for a couple days. if you're tierd than that means your body is tellin you to slow down, it needs a little more rest. try taking "one" day a week to do nothing but rest, walk earlier, dont drink or smoke that day, dont work your brain that day! "just be lazy" wont kill ya to slow down for one day a week.. :) good luck!!!