Hi thanks for your query..first let me tell you that you taking very high doses of vitamin D which can at times cause SYMPTOMS OF HYPERVITAMINOSIS D .mucle cramps can be more appropriately be treated with oral electrolyte solutions and complex of water soluble B vitamins.oral calcium supplementation is very helpful .milk on daily basis would be exceedingly helpful in treating cramps.high doses of vit D is associated with renal failure and bowel disturbances...I suggest that vit D suplementation is stopped.get your self checked for serum electrolytes ,blood haemoglobin,.inj of vitamin B1 can be helpful.consult your genereralphysician for more better options.thank you take care