Dumb by illness - why?

A sinus infection announced itself Friday evening, and I’m not at all looking forward to work tommorrow and the following few days (Yes, I will call my physician in the morning). While the menu at work changes regularly, I know that I’ll be in challengeville for at least the next 3 to 4 days.

And I’m feeling stupid. A sinus infection is not normally a truly debilitating condition - in fact you can live with them for months. But why do sinus cavities full of mucous make me feel that it is particularly hard to think something through?

IANAD but surely anything that involves your body having to use resources to fight an infection is going to tap its reserves, tire you down, and take away resources from other areas?

Plus the discomfort of blocked sinus cavities is distracting in itself.