@Asa I had this other idea, but I'm not sure if it fits or if it goes off topic too much... Last week I read something about how in the late 19th century there was a disease somewhat similar to cfs called neurasthenia. (This was seen as a physical illness, until in the beginning of the 20th century psychiatry adopted the term and made it a psychological illness.) It's not clear if 'neurasthenia' was me/cfs or rather general 'chronic fatigue' or even burn-out. Possibly there was an overlap and it probably was a wastebasket diagnosis for any 'unexplained fatigue' (sounds familiar, right?). The images that came with this disease are pretty interesting...
This article explains it more eloquently : http://sciencenordic.com/chronic-fatigue-syndrome-across-time
This article explains it more eloquently : http://sciencenordic.com/chronic-fatigue-syndrome-across-time