There's a stretch of road local to me where cars regularly get hooted at, on one occasion a friend got an egg thrown at her. I was on this stretch and got hooted by someone in a white van. I flicked him a V sign and swore. Then he pulled up just ahead. I prepared myself for the worst...turns out it was Dave from my running club just being friendly!
As has been said will they let you wear the rig for longer while exercising?
Have you noticed any patterns to when it happens e,g, a particular route, time if day, time related to eating etc? It might be worth keeping a bit of a diary of this sort of thing and see if you spot any patterns that might provide a clue.
Another thought - is there anything about your posture that might be related? In some people it's possible in certain positions that the blood supply to the brain can be reduced, which might cause light headedness.
Another thing that might give a clue is if you notice anything that relieves the light headedness.