I always feel this way when a flu goes away. I know I’m in a fog during it, but it’s a slow dumb slope down. It’s the abrupt coming out, the “suddenly I can think!” which always amazes me.
This reminds me of the fact that ever since I became tall in middle-school, it is ALWAYS insisted that i sit in front because of my long legs. Can’t say i notice much difference, but it’s nice to be thought of.