What Causes Persistent Dizzy Spells?

i have a question i am 29 years old i went to er because i almost passed out well they did a ct scan blood word diabetic check urine test my blood counts normal my blood pressure was 179/109 heartrate 133 its been 4 days now they put me on bp med but i still feel the same theres no sign of stroke ekg came up fine said i am healthy as a ox but everytime i eat i feel like ill pass out when i move my head to fast i feel like ill pass out sitting here writing this i feel like i am about to pass out any advice concerns????