Likely origins for this is due to an infection of some type, if you are experiencing digestive issues then suspect something going on in the gut - this is a prime place for infections to occur. There can be many different infections ranging from parasites to bad bacteria to yeast/fungus. It is important to get tested properly for this http://patrickrambling-pb.blogspot.com/2012/12/lessons-from-parasites.html
Doing a hair analysis can pinpoint mineral levels and endocrine function (such as adrenals) I like Trace Elements Inc. The Adrenal fatigue forum has some good information.