I work in a university, too. Hopefully will be finished with my Master's degree and going into a phd program next year. We will see.
I write lots of notes and pace my work. I try to do mindless things between the things that require thinking. Sometimes I find myself reading the same paragraph of a journal article over and over again without making sense of it (easy to do even if you don't have fibro fog). That is when I stop and do something else. Even a walk outside or a quick break helps. I find if I try to force myself to think, it my brain ties up in tighter knots.
Nasa and other teachers, that happens to me, too when I teach. If you turn it around to the students' advantage, you can say, "so what is such and such called . . ." or "why do you think this happens?" etc. I like to teach statistics and that is something you need to not be foggy on. It is confusing enough already!!
The article I read about coffee said that there is a curvilinear effect - that means as you drink more, you get more alert, but at a point, the ability to do things goes downhill. The graph kind of looks like a hill. I wonder if we build up our tolerance to caffeine and the top of the hill moves to a different place.