On you tube there was a good video about the relationship between narcissistic abuse and auto immune issues and included was CFS and Fibro.
To sum it up.. being around narcissistic people and their bs.. causes us to be in fight or flight. Causing are nervous system to basically go into over drive.. and pan out. If I can find the link ill post it.
It made sense in my case. I was married to a malignant narc and my mom is a narcissist.. I guess that's why I attract them or gravitate to them.. but they literally suck the life from us..