My friends are all out celebrating my birthday. I’m sitting at home in a sulk. I’m considering my options. I could watch TV in the hope that the new instalment of the Nescafe commercial comes on. Or maybe I could watch the news and see what Moira Stuart’s wearing tonight. This, in case you were wondering, is the situation of my life at present. This is Ms Warren’s working party. All marking and no sharking. All cover and no ... well, you get the picture. And I blame my teaching career.

Having your birthday in school is perhaps the most depressing thing in the world. When I was younger, birthdays were the only thing that made school bearable. You took in sweets for all your friends, you had a better chance of being let off homework if you were covered in birthday badges, and there was a general amnesty from playground terrorism. You had a kind of birthday immunity.

From the other side of the desk, it’s all different. You hardly get a chorus of happy birthday in the staffroom. And then, despite the judicious hints I’ve been dropping for the past three weeks, my form remained blissfully unaware of this auspicious day. No card, no big box of Quality Street. No chorus of “Ms Warren, you’re the best teacher in the world”. I keep a list of my form’s birthdays and we have a cake every time. I’m going to start a new campaign: Teachers Have Birthdays Too.

So what do you buy a teacher for her birthday? Board pens, apparently. Courtesy of my flatmate, I now have a brand new set of six multicoloured board pens. This didn’t really start my day off well. “Why would you think I wanted board pens?” I asked him, trying not to sound too aggrieved. “You always say you need them. You’ve always lost them. You spend every morning hysterically throwing things out of the freezer screaming ‘I know I’ve seen them somewhere’. I thought you’d be pleased.” He doesn’t understand that at the moment I need to escape from school. I want to be painting the town red, not sodding marking in it.

I also got this fascinating tome called One is Fun. It’s a cookery book, unfortunately. I wanted something unteacherly, impractical, frivolous. “I want a slinky little number,” I announced to no one in particular in the staffroom yesterday. “Seven?” someone volunteered. At the moment the nearest I get to see-through is a Year 9 homework excuse.

My birthday hit a high spot when I found a half-eaten Mars Bar at the bottom of my rucksack at break. As I held it aloft triumphantly, my colleague looked at me with sympathy. “You need a love life.”

I should have realised this was coming when I bought my new academic diary. There’s a page for every day and two lines for the weekend. Quite apt for the woman who can’t manage words of more than two syllables after 4.30pm every day. It seems that I won’t be swapping columns with Tara Palmer-Tompkinson. I find it difficult to organise my day when it’s not regulated by bells. My flatmate has to go and ring the doorbell just to get me to make coffee.

In fact, I’m lucky that my friends managed to find time to celebrate my birthday at all. The best they could do at first was the Thursday before Christmas. I mean, I could postpone my birthday if it’s more convenient. Cancel it altogether, maybe. My life is devoted to others, so one more sacrifice won’t make a difference.

So all right, my birthday has coincided with a massive bout of self-pity. You’re allowed to have one of those every term - maybe twice if you’re newly qualified.

I’ll console myself by watching my latest cheesy teaching video, Mr Holland’s Opus. My newest scam, I mean scheme, is to teach my Year 7s to say “Ms Warren, we are your symphony”. We could get it right by my next birthday.

Gemma Warren teaches at The Latymer School, north London and writes a regular column in The TES Friday magazine