Tired, dizzy, nauseas...?

I recently got back from an overseas holiday and felt pretty decrepit...dizzy, nauseas, tired and just all round crap. I figured it was jet lag and possibly a bug I'd picked up while my immune system was weak. It's been 5 weeks now and I still feel dizzy...like an off balance, world moving around kind of dizzy, that's always there, but gets extra bad randomly...and I get nausea that comes and goes...usually along with the dizziness. I've been to the doc and had blood tests, which came back ok and he's said to leave it for a couple of weeks in case its a virus. Could it be some kind of inner ear thing? I'm pretty over feeling this way. It makes it hard to work when you're tired, dizzy and nauseas all the time...