When I was overloaded with brain fog, I really think it was because there were too many toxins.
For me, drinking lots and lots of water, eating only fresh veggies, and using P&B shakes fixed it very fast. By P&B I mean that I used Psyllium and Bentonite, available at health food stores. I used them for about six weeks, although I noticed immediate improvement in the symptoms.
You can feel quite a bit better very quickly, if you find what it is your body needs to clear those toxins. Keep your diet VERY clean. Don't worry that you can't avoid toxins 100%, your body can manage some of them. Just not all the candida has been producing. Clear that out and you get quick improvement.
There are other liver flushes, I think they are a little more complicated. I tried making a carrot salad Liver Flush thing, but, well, I'm a baby- I couldn't get it down! It didn't matter...water and P&B turned out to be enough.
I hope it will be for those of you who are struggling with this. Please keep in mind, I did too, and it is over now. You'll get past it too, because you are here and you are working at it and willing to try. OK, enough talk, go take care of it!