Having Malaise, Excessive Thirst and Fatigue

Every few months I used wake up feeling incredibly weak, faint, and tired. It would usually be gone by the next day. A few months ago that changed and it lasted for more than a week and came in waves. One minute I was fine then next I was ready to pass out. One doctor told me I had probably contracted a virus and that it would go away. The other said it was probably my blood sugar fluctuating based on what I ate but my blood sugar test came back normal. Now those episodes have becoming more frequent and gotten worse. Lately I have been excessively tired, been getting numerous headaches, and have a burning in the sternum area of my chest that is followed by excessive thirst. What could possibly be the problem?

hi, wow, exactly my symptons, did you get a response? if so what's the diagnosis?
Tom

TURNS OUT MY HEART STOPS BEATINg i now have a pacemaker and feel better