Sometimes it happens that I feel darkness in front of eyes and dizziness. For a few seconds I am unconscious. When I get conscious I feel some fluid is whirling in my head. Slowly it calms down and I feel headache after that. My age is 56 ys. Earlier it happened 5-6 times in a year. For last 2 months it happened 5 times. Four months before, I have started medicine (Nebilong-H) for high BP about 4 months ago with doctor's advice. When after giddiness I go to Doctor he says no problem is apparent and BP is normal. Doctor please tell me what type of this problem as this causes harm in my normal life when I am alone or driving. Thank you.