For the past year or so I have been sooo tired all the time. I just have no energy. I have tried sleeping 8 hours a night consistently for a couple weeks and it didn't help. I've slept 12 hours a night and I was still tired. I have started eating much healthier thinking that perhaps it was junk food I was eating. It hasn't helped. I drink coffee or energy drinks and I still feel tired! What could be causing my tiredness?