For some reason I've felt awful all day. Maybe it's something I ate. Maybe it's excitement about going away tomorrow. Either way, today I did something I've never done before. I walked out of a lecture I was giving. I was only for a few minutes while I pulled myself together, and then I went back in and finished off. But at the end I felt awful. I was a bit sorry for the chap who asked me a question and got the answer "I'm very sorry, but I can't answer that right now as I have to leave the room for a while...".
Anyhoo, I staggered home and slept for a couple of hours, which gave me enough energy to pack.