Are any of you supplementing with Magnesium?? Vitamin D EATS up magnesium and when you are already low this can be a huge issue. It doesn't seem to matter the version - from the sun or pill form. More Vitamin D means more demand for Magnesium. Many of the symptoms you all have after the sun can be lower levels of Magnesium.
Also aside from Magnesium (which seems to be used the most) Vitamin D uses up Zinc and Boron. Boron is a trace element that helps the balance Calcium to Magnesium
....just something to keep in mind.