It's been a long time since my head felt this drained. Did another one of our presentations and implementation meetings today (not travelling this week, instead they came here). About an hour or so after we had finished I could just tell how my brain got drained and replaced with marshmallow fluff. A classic symptom of having been a bit nervous and then when things are over and done with you relax and there goes the capacity to think straight.
Cure? Watch some nonsense TV and go to bed early. Probably even fall asleep in front of the TV if I know myself right.