Thank you for your help. Femal Age 50 excellent health until 9 months ago. Now ... Severe fatigue, recurring infections. Low body temperature 95 - 97, vitamin d lab result = 19 Low, Free T3 2.3 Low, always cold, severe brain fog and lack of motivation to even bathe, Cholesterol 311, MCV 98 High, Anion Gap 5.9 High,, ultrasensitive TSH = point 97 (.97), Free T4 point 79(.79), B12=334, Monocytes low, eosinophils low, ANA negative, Rheumatoid negative, all other CBC and chem profiles are normal... including ferritin 33.4, folic acid 12.77 and iron binding cap 316.3. My most devestating symptom is the brain fog and fatigue. I have also had a cortisol test 26.2 high and then an overnight dedadron suppression test where cortisol level suppressed to point 9 (.9) low....which was good according to my MD. Can you please suggest a diagnosis or further tests to identify my problem?