Hi, back in August my Vitamin D was very low, 42 ( i can't remember the ranges). I was advised to take a supplement but was never told how much so I guessed at 5000iu per day. This helped for a little while, but I now feel rubbish again with the same symptoms - fatigue, no energy - could it be I'm not taking enough? I can't have another test until spring. Oh yes and I had Tt and lymph node removal 4 weeks ago and RAI coming up in Dec. Any ideas?