You really do need to quit the coffee, it's a sure bet for brain fog if you have mercury toxicity. I get it, so many here have mentioned it too.

Maybe try some oj with a ginseng capsule or two in the morn. Green tea seems to be ok, I water mine down quite a bit and put some xylitol in it. I am truly afraid to drink any high caffiene beverages since my last episode of coffee brain fog which lasted about a week. There are probably other herbal teas or decaf teas that would suit you.

Cilantro and ALA both seem to help brain fog also, assuming you aren't drinking coffee. I am going to get some decaffinated coffee and see how that affects me.

I actually thought that last bought of brain fog was from my chlorella, but no, it was the coffee. I am back to the chlorella without a hitch, I am only drinking green or other decaf tea flavors and feel fine. That coffee brain fog was heavy duty too. It might take a good week to clear up if you have been drinking it steadily, and, if you put the coffee down you'll also find that without the barin fog you don't feel as tired.

Vegetable juice is probably a good idea too like Linda mentioned.