hi sounds like an inner ear problem, i would go to ur gp though and get it checked out and if it is inner ear he/she might well prescribed something that will help with the dizziness and nausea if u get that as well.
Either inner ear or you may even have your blood sugar checked.
If you haven't been eating well, your blood sugar could be too low causing the dizzy/lightheadedness. Also, you should have your blood pressure checked. It's also a sign.. dizzyness and lightheadedness... low BP.