Down with a cold, running eyes and nose, stuffed and sore head. This often happens after a period of lengthy exertion, be it at home or work. I am a strong believer in the correlation between the effectiveness of the immune system and one's general state of fatigue and stress – a few over-worked weeks and those B and T-cells take a little vacation.
A day in bed then. And I will feel better for it in more than just one way.