Very ill, low cortisol levels, please give advice!

Hi, i am here for advice.

My history: fatigue and gastrointestinal problems started in December 2005 and got severely exacerbated. Neurological and cognitive problems followed, with brain fog, clumsiness and loss of coordination in hands, loss of short term memory and confusion, comprehension problems, terrible pressure, burning, and ringing in my head, headaches resembling hangovers. Completely dysfunctional for a few months while trying to figure out what is going on.

This is what my integrative medicine doctor did: put me on antioxidants, vitamins, minerals, herbs for the kidney and the liver. Regular treatments with acupuncture. things started getting better, very slowly. neurological and cognitive symptoms still persisted, energy got slowly better. In August she tested my adrenals (Sanesco Lab) and it showed really really low cortisol levels. She put me on Isocort and I started getting a surge of energy every time I take it. She added DHEA and that helped even more. Also, my memory improved significantly, now I am mentally functional, my brain is a lot better.

However, still terrible headaches and my brain gets really tired from doing even simple things. By the end of the night my hangover headaches and my burning are completely disabling. Mornings are a lot better and I am able to do a little bit of work. Also I am extremely emotionally unstable to a point where i can't recognize myself at all. Have fits of anger and anxiety. No appetite, slight nausea.

Please give me advice! I've had a colonoscopy, an MRI of the neck area (an MRI of the head will be done soon), lyme--all clear.

I am considering mercury toxicity since I was exposed while a dentist drilled out 2 Amalgams without any protection, not even a dam, that was five months before i started getting sick. I've had a neurologist test my heavy metal levels--24 hour urine showed mercury levels 10 ug/L, the "normal" range being 0-20.

Please give me advice! Could the adrenal problem itself be causing the brain fysfunction and the "headaches"? If not what else?