Why don't you have your calcium and vitamin D levels checked? Then you would know for sure, and if your vitamin D is low, you could take supplements. However, if your calcium is in the 10s or above, I would not take vitamin D-- I had that scenario, and my doctor recommended 50,000 IU weekly of vit D for 6 weeks. Over that time, I became increasingly fatigued. That was because the extra D was making my calcium elevate further. Once my parathyroid tumor was removed, I could take D supplements without problem.