The nausea is probably becauase you are dizzy. I had that really bad a few years ago. I couldn't even take a bath because whent he water would "lap" onto my skin I'd get so dizzy like I was on a boat in the high seas! I'd have to jump out of the tub! (diagnosed with begnine positional vertigo), I personally never got nauseated, but that is VERY common with that. But with all those other symptoms, it could very well be sinus problems. (headaches, dizziness, pressure, pain in eyes, etc) - brain zaps? Anxiety from worrying about those other symptoms! I think I know what you mean, it's a really awful feeling like you are "sinking to your death" That's how I describe it.