Single File: People at work talk about the "Friday feeling" - mine is mainly a nagging worry: what am I going to do with Saturday? On Friday nights I make a list for Saturday, then wake up the next morning feeling like the list is my enemy. I rip it up but then start to feel like the lack of a list is another enemy.

It is one of those "all is enemy" days and I don't know how to handle it. Some people would call this the blues; I think of it in terms of how not to be "Saturdayed", and so I come at it with the how tos: how to get through this Saturday, and perhaps one day how to conquer the enemy that is Saturday.

The list I write on Friday has a couple of promises, mainly focusing on the three Cs of cinema, company and coffee. But on Saturday, some of the non-C things creep in, like the launderette, the supermarket and my family - which could be the C of company but more often is the S of stress.

These things that aren't C are dangerous: the L of the launderette spirals into the W of why don't I have a washing machine, and then into why don't I have a house (even though I don't want one - funny how Saturday can be so unreasonable), which spirals into why did my mother call this place a miserable flat, and what if she is right?

I check my watch: that bout of negative thinking has just used up 30 minutes and I think to myself - because at this point I am alone, the C of company looking more and more unlikely - that there is something to be said for negative thinking. It moves you through the day a bit better than the positive stuff, which is all snap-happy, up and at the day.

Just yesterday a positive friend reported something several old ladies had told her at a party - old ladies give it great weight as most have long since stopped worrying about boyfriends, although I think they still fret about their hair and whether they have enough friends and they still enjoy the Cs as much as the rest of us - that "life is to be lived". Yes I thought, life is to be lived and that is what I will do tomorrow with my Saturday. But that was on Friday, and Fridays are notoriously misguided: full of optimism about the next two days, until you end up in Tesco looking for a reduced-price meal for one and a quarter-bottle of wine.

Saturday. The phone rings at 10 a.m. and I fall out of bed hoping this could be a last-minute brunch invite. But it is Deirdre from Eircom making a customer service call. She sounds as disappointed as me when she finds I will answer the questions she is already weary of repeating. I am disappointed but glad of the distraction from the lack of brunch invites. The next call is my mother, and then the call after that is my mother again, with something she forgot to tell me in the earlier one: that voluntary work would cure me of my need for brunch.

Saturdays are a bit like mini bank holidays - on those days I get the urge to phone up everyone in my address book to make sure they each have my current number. I still don't own a mobile, but I sometimes think there must be a phone somewhere taking all my messages.

Being single in your 30s can mean you feel like you are stuck at 20. Saturdays can still equal a film, or going into town to buy the same plastic ring that one of your friends has. It costs five euro so you can afford that. I tell myself again that it helps having a miserable flat and not a mortgage.

Occasionally I do seem to crack the secret of Saturday. I get the content and the sequence right: coffee, work, shopping, movie, cooking and company. But then I start to see this as a formula that will solve the riddle of Saturdays for good, and of course the following weekend it all falls apart. I am exhausted in the coffee shop and angry in the supermarket, I sit at my computer for an hour pretending, and then run to the cinema where I am neurotic.

People at work talk about a Sunday evening feeling. Mine is mainly a feeling of relief. Isn't it great it's not Saturday?