I think there's a psychological element making me cough. Because I gave the same lecture to two different classes, and when I came to the place where I had coughed before, it started again. So, I think partly it's my throat tensing up with worry. But once it starts tensing up it's very difficult not to break into coughing. I am sipping water to try to control it, but I think for the rest of this week I am just going to avoid lecturing. I've more or less cleared the teaching content for the term anyway.
This seems to come on for me every February, and this year it's lasted into March. So annoying.
I am then going to take two weeks off between jobs, because I just need a rest.