As last term wore on, some mornings I would wake up hoping to be ill. A sniffle, minor car accident or even emergency root canal work - all seemed preferable to certain classes I could mention.
Tuesdays often made me toy with the idea of "gastric flu", but I knew from experience that within 48 hours this invariably led to the real thing and could be a little tricky to explain. So I soldiered healthily on, covering for the fortunate ones who were incapable of getting in.
Then the new term arrived, refreshed and revitalised - except I wasn't. By the end of day one, I knew I would have to visit my GP. This was something I had avoided because I had once tutored his daughter and whenever he saw me, he presumed I wanted chapter and verse on her progress. But there was no alternative; I would have to phone in sick.
It was a powerful experience. The last time I felt this way, I was about 13, explaining o a sceptical PE teacher why I couldn't do cross-country. This time, I did feel incapable, but I still had to look in the mirror several times, just to check that I really did look ill. It wasn't the same, however. I didn't have to trudge round the perimeter of the school grounds with my coat on. The school was understanding, even enthusiastic, that I stay at home and keep my bugs to myself. And they were worryingly convinced that they could manage perfectly well without me.
At home, I tossed and turned, trying to work out how many members of staff would be annoyed by my absence. And what about the work I had set? What would they say about that? And where had I left the exercise books? Never again. Extra vitamin tablets for me from now on.
I would much rather cover for someone than have someone covering for me. It was much more fun being ill when I was on the other side of the desk.
Dr Kristina Humphries is a chemistry NQT at King Edward VI high school in Stafford