I am 53 and have gone through the change. I had something similar to this during that time but not as severe. I could not think. In FACT...it is why I joined this forums. I thought I had stress or depression or ......something...I don't know. But if it is like my "fog", magnified, I feel sorry for you...
. It wasn't any fun. I wonder if you may have some strange allergy. Get to a doc, right away, at any rate.