Honestly, it could be every single one of those things. Probably not a strange illness, though. Just allergies, forgetting your meds, wisdom teeth recovery, antibiotics (often make people a little queasy).
A couple of weeks ago I had not a real sinus infection, but inflamed ones due to allergies. I got kinda dizzy at times. Anxiety will also cause dizziness. I haven't experienced that too much, but I hear of it a lot on here. Occam's Razor or whatever: the simplest answer is most likely the correct one.
My Brain: My friend, My enemy: A blog to chronicle my attempt to recover from anxiety/panic disorderanxietypanicdisorder.blogspot.com/