Tay, I spent an entire summer with this problem.
It is usually either allergies, or knots in the muscles in your neck and upper back, which almost all doctors miss as the source.
I have been to doctors for both of these problems separately, and was misdiagnosed at first both times.
After months of being on a med for a " virus " and getting no better I insisted on seeing a specialist.
He diagnosed me immediately as it being my environment and the weather, and prescribed allergy meds. and of course took me off the other ones for the " virus ". My sinuses and ear canals were swelling in reaction to something in the air, causing me balance problems.
The other problem I had at another time was an off balance and fog headed feeling that turned out to be caused from muscles in my neck and upper back that had tightened up and were pressing on the blood vessels going to my head affecting the oxygen supply.
The symptoms are so similar that it helps if a person can remember exactly when the symptoms started, time of year, what the weather was doing, and what you were doing physically at that time to narrow it down.
The muscle problem does not have to cause pain so it is usually overlooked, but a very common problem.
To this day, it will take me awhile to realize which is causing my symptoms.
I now can check myself, my own muscles, to know if I need to go back to PT.
And I now am on allergy meds almost daily as I will wake feeling drunk with swollen eye lids, unable to think straight, and feel very tired and off balance.
Good luck to you and I hope this helps and you get some relief.