I wrote, “The life Maria booked had let her down”. I should have written, “The lifeguard Maria booked had let her down”, which just shows that when I’m in one of my vague moods I should probably stay in bed where I can’t create so much confusion. (Nice meter, though, don’t you think? Perhaps I go poetic under stress.) Writing the minutes for the summer activities programme is a relatively safe activity, but I have lots of other important roles that are not compatible with a stressed-out brain, being vague, making bad decisions or simply getting things wrong. Take this morning, when two supply teachers arrived to cover the same absent colleague or when I was making notes during an appraisal meeting and wrote down the wrong person’s name throughout. Luckily, Becky understood but she did point out, as she looked over my shoulder, that whereas she had asked for more training in behaviour management, I’d written banana management. Don’t analyse it. It was just a mistake.

People react to stress in different ways. Some of my colleagues get angry and negative, some get depressed and quiet, while others are assertive and have strong survival mechanisms. They will phone in sick, saying they’ve been overdoing it and need to rest. They return refreshed and ready to carry on whereas I feel worse than ever having had to cover their duties as well as my own. I may sound resentful, but I admire this approach and think it would be healthier if we could all recognise when we need to recharge our batteries.

The problem is that we know we are leaving colleagues in the lurch when we spend a day investing in our own health, sanity or family life, and schools don’t usually have the capacity to cope with fluctuating staff attendance.

We’re lucky in my school, where there is trust and an acceptance that if someone rings in sick, they are sick and need to stay at home until they’re better again. I’ve heard of other schools where people are made to feel guilty if they have time off and have to attend a return-to-work interview if they leave school 10 minutes early for a dental appointment.

It’s obvious when I’m under pressure as I make increasingly bizarre mistakes. I have occasionally staggered into school under the influence of a migraine and a cocktail of painkillers washed down with caffeine only for my colleagues to drive me home again. The school is much safer without me.

As the third supply teacher turned up at school this morning, my head looked at me and shook her head. “Take the rest of the day off,” she implored, “and don’t come back till you’re better.” “I will,” I said, putting my memory stick in the fridge and stuffing a carton of milk in my brief case. “I’ll go for now, but I’ll be back ‘ere long.”

More iambic pentameter. Did Shakespeare suffer from stress?

Maria Corby is deputy head of a special school for pupils with severe and multiple learning difficulties. She writes under a pseudonym