Maybe switching to a D3 by another company would help. Do you think there is any chance it might have a filler in that you are allergic to? “Bio Tech makes D3 that “meets rigorous FDA standards and their product is void of dyes, talc, binders, artificial colors and synthetic flavors.”
Second is that Vitamin D uses a lot of magnesium to process. If you are deficient then you can get symptoms from that which may include: fatigue, headache, nausea, insomnia, muscle cramps, weakness, constipation and anxiety. But who knows what else a lack of magnesium may cause. It is used throughout the body and a lot is needed.
So maybe one of those things will help!