just an odd thought:

A few years ago (during summer) I was so tired - like sleeping 18 hours a day and dragging hiney the rest of the time. MD kept saying it was neuro related. Due to the lab running a test by mistake they discovered I had developed Hashimoto's and was super hypo-thyroid.

Doc sent me to endo MD and he slapped me on Synthroid right away. Once the dose was adjusted I felt worlds better. Heck, my regular doc missed the signs, since everything else was related to the MS like issue.