What Does Fatigue And Dizziness After Being On Effient Mean?

Hi, my name is John, I am A heart transplant patient...my health history is very long but for about 2 weeks now, not every day, I stop breathing after I fall to sleep, I'm very tired, dizzy, had a couple of stents put in about 7 month ago and when I go to the E.R. all the test R negative...I was put on effient (prasugrel) in June 2010 and in July I started having issues with my stomach