I lost control and hit my son

I am writing this at 2am. This in itself is stressful. In the past year I've begun to recognise the symptoms of stress all too well. I have them right now: a little crackle of electricity as the mind whirs in a thousand directions, insomnia, a hunger for caffeine and chocolate, the encroaching thud of a migraine. And the more stressed you get, the less you accomplish; hence, being hunched over the laptop at a ridiculous hour.

Stress rushed into my life in a greedy, ruthless way, when I was outed last year as the anonymous author of a book, The Bride Stripped Bare. I set out to write a novel about a married woman who has an affair - I wanted to be unflinchingly honest about women and sex. To say all those things we may think, but never admit - especially to our lovers; to examine the complex, dark, secretive underbelly of female sexuality.

It was, needless to say, controversial. I'd fully intended to put my name to the book when I began, but soon found I was censoring myself: afraid of too much honesty, and afraid of hurting people closest to me.

When the idea of anonymity came to me everything clicked - and I felt it gave me the sort of control I was desperate to cling on to. Ironic, then, that that need for control compounded the stress I was undoubtedly susceptible to.

I'd opened a door to a reckless, exhilarating new world where I could be utterly truthful about these issues for the first time in my life. It felt wonderful, powerful, an enormous relief - but it was then highly traumatic to have to own up to it as a wife and mother of a toddler and a baby, not to mention a daughter of two gently bewildered people in their sixties.

Just a fortnight after the manuscript was sold I was unmasked by the press. I then lost control of the book, and my life: stress, I think, has a lot to do with an inability to dictate circumstances around you. Uncertainty, in whatever form it takes, is extremely destabilising.

And, yet, in this modern world, we expect to be in control of so much of our lives - from the time our new sofa is delivered to the way our latte is made at Starbucks, to what school our children get into. We have more choice, more knowledge and louder voices. When we can't control what we think we have a right to, we get stressed.

The day Bride was released my publishers insisted on a celebratory lunch. Okay, I said, I'll treat myself: dressed to the nines, I got a minicab to the restaurant. But on the way I started weeping uncontrollably; as if I was grieving. I couldn't stop. The driver kept on turning around in alarm and asking if he should take me home. "No, I'm fine," I insisted.

For half an hour I wandered the streets of Soho wracked by huge, gulping sobs. I was unable to walk into the restaurant, unable to face it. Strangers asked if I'd like to sit down, ring someone, have a glass of water. They showed me kindnesses that cracked my heart and yet I couldn't tell them I was crying because I'd written a sexually explicit, excruciatingly honest book, and felt like I was falling apart.

I was dreading the reaction from friends and family; most of all from Andy, my husband. Worried I'd shot my career in the foot. Couldn't sleep; couldn't shut my brain down at night; desperately tired and thinking maybe all that was needed was Valium, but scared of the slippery slope it could lead me down.

It felt like my life was imploding. I couldn't finish sentences or complete the simplest tasks - freshly washed clothes were heaped in my sons' bedroom and phone calls went unreturned. Taking umbrage at the slightest hurts, unable to cope with the simplest situations. Snapping horribly at people around me. All my defences were down. I felt as if I was on the edge of a cliff and the most inconsequential thing would push me over.

On an afternoon shortly after Bride came out, my three-year-old, Lachie, wanted something and began a whiny tantrum. He wouldn't stop. I hit him. I'd never hit him before. He just looked at me in bewilderment and alarm and then burst into great howls of outrage.

I rushed him into my arms and held and held him, and wept too: for what I'd done, and for the woman I'd become. Stress had driven me to a place I'd never been to before. It was like a rampant weed affecting every facet of my life, even the most cherished.

And yet writing The Bride Stripped Bare had been all about control. At my desk I'd entered this strange, liberating psychological state of secrecy: as if I was stepping out of my everyday self and becoming someone much more confident.

When I was writing I felt calm - but didn't anywhere else in my life. For, as a freshly married wife in her mid-thirties, with a toddler and a baby, I'd suddenly lost control of my world, the migraine-free world of a single career girl who'd always called the shots: what she ate, how much sleep she got, where she spent holidays, what sheets she put on the bed. I'd been disappearing into the strange new land of the homemaker, where I often forgot to eat because I was so busy tending to the needs of everyone else. Where I'd sometimes end up crying over the dishes in the sink for no other reason than that I was exhausted. I was dealing with a new sense of erasure; a feeling that all the promise and vividness of my youth, all its loudness, was being rubbed out.

After Andy read The Bride Stripped Bare, he started noticing me again. As a woman - not just a wife. He survived the book coming out and was actually turned on by it (a response I'd never anticipated) - but what desperately worried him was the new, stressed companion he'd been landed with.

The only way to beat anxiety is to acknowledge it; to stop pretending everything's okay.

I've tried controlling it by saying "no" more often, and not feeling guilty about it. Having a bath at night to ease me into sleep.

Finding some restorative pocket of "me" time somewhere in the day.

Never getting to that point again of wanting to hit my child.

I'm now out and proud, so to speak. And I've surrounded myself with positive people, which has meant distancing myself from friends who've flattened me repeatedly. I've found the courage to say "no", enough; I want to be surrounded by heart-lifters, not heartsinkers.

It doesn't always work. Recently Andy came home at 6pm to find me curled in a foetal position on the kitchen floor, Lachie and my baby, Ollie, trying to fix Mummy with sticking plasters and a bottle of unopened Calpol. I couldn't lift my head, felled by a migraine that felt like an axe embedded in my right eye.

Stress is a condition more debilitating than I ever imagined. You feel weak, vulnerable, embarrassed to admit it. You're confronted by an attitude from some people of "come on, handle it, get a grip". That's patronising, for it's not some phantom condition.

Ollie's just recently started going to the toilet and making vomiting noises into it - copying Mummy having her headaches. He thinks it's hysterically funny, but I'm not laughing. When Lachie says "don't shout at me, Mummy", it breaks my heart, and brings me up abruptly. It tells me I'm stressed again; and it's not his problem, it's mine.