Always thirsty very very tired?

Im 15 for awhile I've been very thirsty like at lunch I but 2 water bottles and I finish them in like an hour I've been sleeping a lot like I fal asleep at like 6:30 my feet have been falling asleep I get headaches and I go to the bath room alot. I was test for diabetes two years ago and it was negative. What's going on?