Hello and hope you are doing well.
As discussed there is unlikely to be an allergy to vitamin D. As it is a fat soluble vitamin, hypervitaminosis can occur, the symptoms of which are, vomiting, polyuria (frequent urination), weight loss, poor appetite, constipation, weakness, heart rhythm abnormalities and kidney stones
Treatment of vitamin D toxicity includes stopping vitamin D supplements and restricting calcium intake, as well as taking medication. But it is unlikely in your case, as you have a deficiency of the vitamin.
Hope this helped and do keep us posted.