Five-minute Memoir: Jenni Fagan remembers being pregnant

The bus smells damp, it's snowing outside and I am going to be late for tutorials if this traffic doesn't start moving. Trafalgar Square appears and Nelson is scanning the horizon. I used to do that in crowds, unconsciously hoping to find a similar feature to mine. I've never met anyone I am related to, well, my father a few times in my twenties, but other than that – nothing.

Now I have two heartbeats inside me, where before there was just one. There is still a faint residue of gel on my tummy, where the nurse coated it earlier. On the screen – your hands covered your ears, you were dreaming, floating in space, unaware of us peering in at you. Your heartbeat sounded so strong, the sound filled the room and the nurse turned to me and said – it's a boy.

I cried.

You are no longer an abstract it, you are my son. We walked to Tate Modern and I played you Tim Buckley on my headphones. In the Turbine Hall there was a huge cargo container lined with black velvet. Stepping inside – it grew darker, until everything was black. That's how I imagine dying might be – like walking into darkness. I'll tell you about death another day. It's nothing to fear. Hopefully I will pass on a long time before you do and I promise if there is a cargo container on the other side of life, I will be there, waiting for you when you arrive. You will be old and wizened then, a little old man – who once was a boy.

We took a few porcelain sunflower seeds from another exhibit, each one was handmade and is totally unique. I keep touching them in my pocket and wondering what I can tell you about life?

The truth of it is this – we live in a world without explanation, in a galaxy and universe surrounded by galaxies and universes and nobody asks questions too loudly because the answers are sketchy at best. I can't explain to you why we arrive as seeds and leave as dust, but I can show you the truth in rainbows. I can bake you pancakes, and take you to the park in autumn so we can kick up the leaves.

The bus turns onto Shaftesbury Avenue, the pavements are crowded and I wonder if we'll raise you here. I want you to spend your childhood by the sea, somewhere with huge skies and open spaces.

I know you already, we are intrinsically linked in a way that I have never felt with a stranger. I was always walking into some new foster home to live in, or a kids' home, or an adoption – the perpetual new kid. Over the years I began to observe families, how they functioned. I studied them because they never worked out for me.

This is different, we are a part of each other, and I will do everything I possibly can to give you a happy, secure life. I feel like I'm growing up, placing my two flighty feet, firmly on the ground. The bus turns onto Oxford Street, and I ring the bell to get off and realise I won't be late for class after all.

Here we are. Two heartbeats. You and me. I pull my hat down, tie my scarf and hold the handrail as we go down the steps. I'm wearing wellies, and jeans, and my jacket is zipped up to my chin. I'd never wear wellies before but you make me want to keep my feet dry.

We step onto the pavement and an old man swerves by us, singing loudly in Italian. His coat is covered in shiny badges. He gestures at passers-by as if he is ushering them off a plane, and they try to avoid him.

This is life – in all its smelly glory! I hope you can forgive me for bringing you into it, especially if you think too much like I do. It's OK really, the ache of being alive, the beat of your own heart, the silence of unanswerable questions. There are shooting stars, and music, and there is magic if you learn how to look – and it is still our world, no matter how many other people might try to convince you, it's mostly theirs.

It is yours and it is mine.

And all these other people walking by us in the snow, it's their world too.

I touch my tummy through my coat and I know you are awake again. The sunflower seeds in my pocket feel cool, and smooth to touch. We will wait for a few years, then we will go and plant them – somewhere on a cliff-top, where there is a view of the sea. We'll let them nestle in the cool soil and water them on weekends. After all, who says – that porcelain seeds can't grow?

Jenni Fagan's novel, 'The Panopticon', has just been published in hardback by William Heinemann. It has been picked as one of Waterstone's 11 debut novels of the year