In my experience morning wood is related to DHEA levels. That is one way--along with followup blood tests-- that I gauge my intake of DHEA. For me that is only a tiny dose of 6mg two or three times per week.
I think it is wise to also include pregnenolone in the blood test although a doctor might not. It is the grandmother of the cortex hormones. If preg is low-norm and you feel a little better with 10mg x2 or so you have a puzzle piece. It is much less expensive than most other adrenal support options.
Have you tried to slow down Liver Phase I and support Phase II? This takes the edge off of the MCS for some people but they often struggle to tolerate the things that theoretically should be useful. Finding a better diet with fewer chemical additives, phenols and salicylates might be somewhat helpful.
"Naturally sensitive" or mercury(Hg) + arsenic fouling up your liver as they tend to do.
The adrenal cortex hormones are one of the most vulnerable systems to mercury. Boyd Haley, former chair of the chem dept at the U of Ky says the hormone receptor for several stress and sex-related pituitary hormone, ACTH,FSH, etc holds onto mercury about as well as anything can. Haley warns that levels of mercury in the blood will be similar to levels of ACTH when a person has 6-12 or so Amalgam fillings--contain 50% Hg.
That form of Hg easily crosses the blood brain barrier. Some of that naturally gets converted to inorganic Hg while in the brain. Inorganic Hg doesn't pass the bbb at a medically useful rate and so essentially gets stuck there to mess with control of hormones, memory, personality, mood, etc. I've been there : ( Thankfully improving with detox--Cutler.