have you ever looked up the possible connection to high and low frequency radiation? Such as microwaves from mobile phones + masts and the ever sending DECT Cell Phone s (base station) and WiFi (router sends also day and night with 10 Hz pulse frequency).
EMF are know to drop down the immune system. I suffer myself heavily from EHS.
http://www.bioinitiative.org/
is usually a good point to start. There is nothing else then being protected from not being cooked in 6 minutes official "limits" are good for. They are zillion times to high!