My cortisol was high all the time for 3 years and I am going on month 3 months of it staying in at a lower level. My sleep was so so horrible. At one time I would just lay there all night. Along with the supplements you have to retrain your brain. You need to let your nervous system know your relaxed now. It took me six weeks to do this. I did binaural beat meditations, and The Healing Codes. You really have to convince your mind that things are going to be calm now. Alot of the posters here that have normalized their cortisol levels have done similar techniques.
I also took a lot of the supplements Gavster is suggesting. I took a B complex sometimes 2 -3 a day. It took me a while to figure out a healing routine that worked. Sticking to this for sixs weeks helped me recover quickly. Now my health is a little fragile. I push things to far sometimes and crash.