I Have RA And A Couple Of Months Ago My

I have RA and a couple of months ago my rheumatologist said my vitamin D was low and wrote me a prescription for vitamin for D-3, 50.000 IU to be taken once a week. My primary care physician said he didn't want me to take it because there are reports that people taking Vit. D have more probability of falling. Lately I have been extremely tired and my bones have been very sore, as well as my joints. What would you suggest?