If your symptoms are intermittent, self limiting, and concurrent with your viral sounding illness, I wouldn't be too concerned. It sounds like you've got a bit of sticky fluid stuck behind your eardrum, affecting your balance mechanism.
Unfortunately, there is probably no cure other than time and fluids.
I suspect you 'aint a wuss, just male- never underestimate the effect of "man flu."
Again, I wouldn't be to worried about the connection with sinusitis, if things are intermittent.
Oviously, you shouldn't fly if affected....contact your doc if things persist ....blah blah.