So starting about a week ago i started having trouble taking deep breaths when I felt I was tired, but when i went to school today when I was in the middle of class i felt like i was going to fall asleep. When the period ended I stood up to walk to my next class, I felt dizzy. The shakiness happened when I was walking too, but the weakness is only in my arms though. I'm 15, around 5'8, and I weigh 174 pounds if you need that sort of information.