This is very weird.  I am actually a physician, a pathologist, with mild MS and recently have been very tired, and also had many GI symptoms like severe constipation (scope showed chronic active gastritis).  My TSH came back 5.4, so now on thyroid replacement hormone, more alert, but still tired, thought it was the MS, or the Sjogrens autoimmune disease, which I also have (everything overlaps). I just keep on working and going, any improvement is better than nothing.  But now I find out I'm vitamin D (and B12) deficient, even though I eat a lot of red meat and a lot dairy foods.  Vit. D level is slightly more than yours though at 13. I am not sure if there is a connection between vitamin D deficiency and MS, never actually thought about it.  But now I guess I have to research it.  I am on vacation for a few days, so will do this.  It is nice to know some else has these crazy problems too! Marianne Murphy