I've been reading a number of your posts and we have some strong similarities, even though our root causes may be different. The Histamine info is bang on, I've noticed this for sometime (due to an infection with Blastocystis I have) and have always felt better on supplements that lower Histamine (ex. Vitamin C, Methionine, TMG, Magnesium, and Diamine Oxidase).
I agree to stay away from the Vitamin B12 and Folate (in any supplemental form) if you feel you have High Histamine. Both can cause a huge rise in Histamine and cortisol is your first defense for lowering Histamine. It's no wonder Cortisol is constantly pumping out, and therefor draining your adrenals.
Otherwise, keeping to a Low Histamine Diet as much as possible. If you do want to have some Histamine containing foods, I would look into Diamine Oxidase (one of the enzymes that breaks down Histamine) to take BEFORE you eat high histamine foods.
After dealing with that finding the cause of your raised histamine (gut issues, copper issues, ....etc...) is naturally another important step)
**NOTE - This is NOT to say this is the cause of all Adrenal Fatigue - only that Histamine and/or Unavailable Copper really is messing some of us up**