Are you on bipap?
If you're having shallow breathing from the doxycycline, it wouldn't hurt to bring this up with your doctor.
I take a dropper-full of blue berry juice concentrate every day, also a serving of barleylife powder reconstituted, and fish oil as well. These are all good for the brain and the rest of the body too. I will confess to enjoying being able to put it all (especially the barleylife) down the tube now
My memory and cognition is good though. I notice more 'fog' when I don't take the fish oil in particular.