Why do I get sick taking Vit D? My story, I used to take 5000 Iu daily until I got sick with an autoimmune disease called Sjogren's/ After that happened whenever I took that dose my hands swellled up, so I stopped. My levels stayed in the mid 20's for the last few years without any supplementation, then I suddenly got a test back and it was 9 ng/ml, so I tried taking it again. I started slowly at 400iu, but my limit was 1200 iu before I woke up the next day with a hangover. No matter what I do I cannot go over that dose. I used different brands, natural food sources like cod liver oil, synthetic and even D2 (2500 iu). but always the same. Why is this happening to me. I want to get me levels up,but cannot do so, I have sun sensitivity, so that is out. All my blood work is good, nothing is out of range, on paper I look very healthy! Help me find an answer, my docs do not have any clue either. Thanks for reading this.