Just a thought... I bumped into this interesting article regarding Vitamin D and here is a quote you may want to think about:
"...clinical signs of vitamin D toxicity: These include kidney stones (also a sign of vitamin K2 deficiency), low appetite, nausea, vomiting, thirst, excessive urination, weakness and nervousness..."
Full article here:
Since you mention you are adding to your prescribed dosis of Vitamin D, I'm wondering whether an excess of Vitamin D could be causing those symptoms? How does the timing of you symptoms fit in with the start/increase of Vitamin D supplementation? If I were you, I might expreriment with discontinuing the Vitamin D supplements for a while and see if the symptoms improve. Unless of course you can afford to have a blood-test to determine the levels?
There's further interesting discussion on the issue of Vitamin D toxicity on the below article, and I extract what I find most relevant here:
"Before closing, I must mention (briefly) the issue of vitamin D toxicity. Vitamin D is widely considered to be the most toxic of all vitamins, and dire warnings are often issued to avoid excess sun exposure and vitamin D in the diet on that basis. The discussion of vitamin D toxicity has failed to take into account the interaction between vitamins A, D and K. Several lines of evidence suggest that vitamin D toxicity actually results from a relative deficiency of vitamins A and K."
So you may want to think about your vitamin A and K levels if you are supplementing Vitamin D and getting symptoms?
All the very best!