I m 19 years old, 5 2 , and weight approx. 140 lbs. I don t have any notable medical history (but mostly because I don t go to the doctor very often). My problem is really sudden and terrifying dizziness bouts that happen occasionally. I ll be sitting in front of the computer or in bed reading, when I ll feel like the world decided vertical was better than horizontal. Beyond the reversal of up and down versus left and right, I ll be completely conscious and more than terrified. What s happening?