Are you taking any magnesium, GABA, maybe a couple mg of Li from lithium orotate or similar?
Do you take any other support for adrenal cortex--cortex glandular, pregnenolone. progesterone cream, etc?
Cortisol is only one of many adrenal hormones; however if you can't convert upstream hormones adequately I would not expect the supplements to replace the predinsone. http://en.wikipedia.org/wiki/File:Steroidogenesis.svg