I would not suggest taking Hydrocortisone/Cortef, but I do take it. Once you are on it, it's very difficult to taper from it and you always must make sure you have some on hand, otherwise your body will go into an adrenal crisis. Also, it helped me moderately for 2 weeks, but after that I relapsed back to the original fatigue and symptoms I had before taking HC. The only 'benefit' is that it increases your appetite, which is the ironically the main reason my dr. prescribed it for me. He guessed I had AF, but said that my low weight and low BMI worried him the most, so he started me out on HC. I've been on it a year and can't wait to some day start to taper off of it.
Never had cortisol tests done, but my lowest levels (based on symptoms) have been at night.
That said, I take 12.5 mg a day.
7:30 am: 5 mg
12:30 pm: 2.5 mg
4:30pm: 2.5 mg
8:30 pm: 2.5 mg