Do I a Sinus Problem?

My head feels extemely heavy!! I have moments like I was about to p out and went to the ER and doctor a total of 5 times!!! Everything came back normal!! I always feel weak and it gets better when I eat sometimes , my balance is off and it cont. feels like im floating..please note that this symptoms are extreme and not mild! I feel horrible and also note that I have had moments of anxiety because it felt like I was goin to faint what is this whats going on?