You could use an adaptogen like phosphatidylserine to resensitize your hypothalmic-pituitary-adrenal axis to cortisol and reduce overproduction underproduction cycling. The theory I put forward is that Grok got to eat brains once or twice a month which is a rich source of PS, but very few of us eat brains now - see:
for more details on selecting the type of PS to take. I use the Enzomatic Sharp PS Gold (conjugated DHA) encapsulated by a few different brands, but there are better forms starting to enter the market.
The book Primal Body - Primal Mind by Nora Gedgaudas has an excellent section on explaining and addressing adrenal fatigue/exhaustion.
Underground Wellness also has a podcast on it: http://www.blogtalkradio.com/undergroundwellness/2010/10/07/the-truth-about-adrenal-fatigue-with-dr-bryan-walsh
I've had severe adrenal symptoms for a long time, and have experimented with everything, I mean everything to get better. Currently, I'm not on any supplements, no medication, and not drinking any caffeine whatsoever. I just eat strict meat, fat, veggies, and fruit, and rare cheats, but no caffeine. Once I went caffeine free I began to feel dead tired throughout the entire day. HOWEVER, even though I'm incredibly tired, I'm mentally stable again which I haven't felt in over two years. I'm hoping the immense tiredness is my adrenals healing. Before, I would get really tired, but then really hyper all in the same day. This consistency of tiredness feels better.