I am experiencing bad dizzy spells for a long time. The other day I walked on the tread mill for 30 minutes and when I was done I was very dizzy and vomiting. I had to close my eyes and lay down. I have them when I tilt my head back side to side, if I roll over in bed or just change my position. My doctor told me about 1 year ago that I had bulging ear drums and to take Zyrtec every day but it doesnt seem to helk much.What could be my problem.