At which point does a common cold become a genuine reason to phone in sick, draw the curtains, stay in bed and coddle yourself? When neon-green snot - more akin to ectoplasm than regular body fluid - will just not stop flowing? When the hacking cough has all but shredded a previously healthy set of lungs?
I have spent the best part of this week trying to convince myself that I will not be defeated by such a bog-standard ailment. It's just a cold, after all; a mere inconvenience, not a reason to shut up shop.
It began on Monday morning; a little twinge in the throat. On Tuesday, I woke up to the feeling that my skull had been pumped full of wet sand. On Wednesday, I was semi-blinded by the continuous watering of my left eye.
But being a good soldier, I armed myself with tissues and vitamins, and battled on.
There seems to be an unspoken code in teaching that if you're able to stand unaided for more than five minutes, you're fit for work. Having time off is more hassle than it's worth: on your return, it is likely that your well-ordered class will have become some sort of re-enactment of Lord of the Flies. The stationery drawers will be a horrible mess, and the poor supply teacher will be found cowering in a corner, rocking backwards and forwards, repeating the words: "Please let me out".
Not for me. I'd rather claw my way to school than have to spend weeks reprogramming the children on how to behave.
As for my cold, well, it's taken a turn for the worse. But, hey, it's the weekend, so I'll cancel my social life and catch up on that overdue recovery.
And if my nose wasn't quite so blocked, I might also catch the smell of burning martyr
Louisa Leaman is a London teacher