Here is the NHS guide to Chronic Fatigue (CFS/ME). Click icon to browse.
It seems to have taken a good few years for ME to become widely recognised across the medical profession as a genuine and debilitating condition but things seem to have improved a fair bit in that respect. This has been in no small part due to the work of groups like the ME Association. They are a UK national support group for people with ME. Click icon for their website.
Autistic burnout seems to be an informal phrase used in the autistic community. Click play button to watch a video by Amythest Schaber. She seems to have a clear understanding of the issues and presents them well. Also: