In the past three days I've noticed that when I move quickly, especially from sitting to standing or lying to sitting -- I do a lot of yoga -- I get sharp, dizzying pain in my head. Sometimes in the center, sometimes in the back or to one side, and occasionally in the temple. I've been out of town so haven't checked my blood pressure. I"m on Exforge and Crestor, 5'4" and 140 lbs. No ringing of ears, like when BP high. Generally low number has given me a problem, but lately overall BP around 120/80. Am I about to have a stroke or aneurism?