Don't complain . . . . . I've been like that for two years or more! . . . . . and I haven't even started treatment yet!!!!!!! Yes, it's that mercury doing its thing. Lack of brain function has been my biggest response to mercury - or at least the most scary. If it helps, my test for brain function is to play Free-Cell patience on my computer - when the computer starts "cheating" I know I shouldn't drive or use machinery. It is a more subjective test, because it is probably not likely that the computer could cheat.! If you are unfamiliar with Free Cell, all the cards are displayed face - up. If you really cannot find a specific card, it logically has to be your brain which cannot "see" it.
Hope this is some help to you.
I'm only on the beginning of the journey myself, so I hope I don't get too much worse once I start treatment!