I am posting to try to help anyone else who has suffered as I did for 26 months. It all began after hitting my head when I fell on ice. I had an CAT scan, it was fine. I went to many doctors complaining about my low grade fever (up to 101), extreme fatigue, mental fog, weight loss, muscle aches all over, and never feeling rested. If I tried to do things with my kids that required any physical activity I would be in bed for 2 days too tired to get up. I thought I had an ongoing tick borne illness that had never been treated and had been not causing many problems until I hit my head and caused my body to be so stressed that the bacteria were able to take over. I was tested for many tick borne illnesses, had a bone marrow biopsy (painful), and so many more tests and blood work. Nothing! Finally I saw an episode of "Wrong Diagnosis" where the girl had hit her head during a car wreck and had the same problems as me, she had low Cortisol from damage to her Pituitary gland. I went to an endocrinologist right away and sure enough my Cortisol was on the low end. I am now taking Hydrocortisone...forever. The scary thing is that if someone with low Cortisol is in an accident or has any major trauma or stress in their life they can go into shock and die before anyone knows they need more Cortisol as this is how your body deals with the stress. Even while on replacement therapy you need an extra dose. Also need a med. alert bracelet and an at home injectable dose.