About five years ago, my 8 a.m. cortisol was trending above range a little, with a high-normal ACTH. Starting two years ago, it started trending down. In the beginning of last year, it was at the bottom of the normal range (around 5) with an ACTH sitting inappropriately low-normal (around 11), and my new endo did a Cortrosyn stimulation test in September. It came back 0.2 points BELOW the cut-off of normal stimulation(18 is the cut-off), but he said I was just fine and it was nothing to worry about. (I beg to differ). From my research, I think I have a pituitary that is not working correctly, so it isn't signalling the adrenal to put out cortisol. That is Secondary Adrenal Insufficiency. When my cortisol began getting lower those two years ago, I also got what I call a new case of having CFS. I used to have POTS but plenty of energy to want to do things but couldn't because of POTS. Now, my POTS is actually better, but I have no energy or drive to do anything.