I have decided to pause taking Vitamin D for a week or so to see if that helps my "lightheadedness. That is not the right term to describe what I am experiencing but it is the closest I can come to that. If my body builds up to an off the scale reading for a water-soluble vitamin, what does it do to a fat soluble one! I have found I can keep my Vitamin B12 level at a safe one by taking it only once a week. Michael's comment about possible increased risk of falling registered with me. Although weighing less than 100lb, I do not have a lot of fat to store the Vit D in.