I've heard countless reports of the benefits of low dose hydrocortisone or similar in the adrenal support groups and heavy metal detox groups.
Supplements such as pregnenolone, glandular, vit C & B5, etc can also be helpful for those who don't have such a difficult case.
They can allow some people to take less HC medication. That is helpful when the person is gaining weight on HC
Many health problems can be involved in fatigue and some people have more than one such problem. This so often seen in the detox groups where toxins affect adrenals, thyroid, pituitary, mitochondria, digestion, liver, etc.
Have you gotten convincing tests such as the one described here.