Hi Lisa, Although I've not been diagnosis-ed with MS, I feel pretty confident that I may have it.  My doctor did check my vitamin D levels, since my complains started with feeling sad, body fatigue, muscle spasms, tingly limbs, etc.  I currently take 4000 IU.   But I wanted to respond to you because on 2 occasions recently I have been told that those of us who have low vitamin D would experience the benefits of it if we took 50,000 IU 1-2 a week.  A naturopath recently told my brother-in-law and my friend who is a nurse with sarciodosis both said that the higher dose less often is better because otherwise its often not absorbed through the body. Regardless, you should check with a healthcare proffesional.   As for all of your symptoms leaving you feeling low, I hope that you feel relief and joy this weekend.  Do something nice for yourself- you deserve it!