Could it be Meniere's disease? See an ear, nose & throat specialist. I had it. One's body retains too much fluid in one or both ears. I used to faint when I exercised. There are a couple of things doctors do. The most important is reduce salt intake to practically nothing. The doctor may prescribe a diuretic. There are other pills, too.
What do you mean by "starting to lose balance?" Is it vertigo? Are you able to walk? Is it 24/7 that you can't stand straight without trouble? Dizzy?