I hear ya, ShyGirl.  
I've started drinking a can of Sugar Free energy drink (lidl - 29p per can!).  Same effect as coffee, but tastes nicer.  I've never needed this in the past (and I actually considered that those that did drink coffee were 'cheating'!) - but it's definitely helped me.
Getting BG down also helps with lifting the fog.
The good news is, it's not a one way street.  You can get your old brain back!  (Thank God!)
Sounds like you may need a med review, too.  What are you on?