Feeling Dizzy, All The Time, It Get Worse When I

feeling dizzy, all the time, it get worse when i enter big stores like Walmart..etc, sometimes it gets bad after food. most of the time tired and want to sleep. not focus ,feeling just i want to close my eyes and sleep.i did cardiology testes last year and all were good, i just did complete check up and my cholesterol is little high(206) which doctor should i go next..
P.S i drink lots of water every day.