I opened my eyes with a start, breathing heavily, my pyjamas drenched in sweat. I must have had a nightmare, I told myself. But as my eyes came into focus, cold fear gripped my belly – I realised I had no idea where I was; my nightmare was real. Where was my lower bunk bed and my pink bedspread? Why wasn't my sister sleeping soundly above me? Why couldn't I hear my parents making breakfast downstairs? I scrambled from the king-size bed I'd woken up in, frantically looking around the room for something I recognised, some clues as to how I got there. Had I been kidnapped?

I didn't know it yet, but I was suffering from a condition that wiped all memory of my current life as a 34-year-old mother and catapulted me back into the mind of my 15-year-old self.

Cautiously, I walked out of the room into a hallway, hoping to move into a state of recognition. I called out, but the voice bouncing off the walls didn't sound like me. Troubled and disorientated, I opened a door into a bathroom. While the room was unfamiliar, what shocked me to my core was the face staring back at me from the mirror. It was me, but an old version of me, a version fast-forwarded in time. I was 15, yet I had an adult's face – laughter lines, crow's feet, dark circles under my eyes, which were now welling up with tears.

Panic kick-started my legs into gear and I sped out of the room and down the stairs, bursting into room after room I didn't recognise. I didn't know what I was looking for, perhaps for a giggling friend to jump out and yell "Surprise!", or for my parents to sit me down and explain what had happened to me.

I scanned the pictures on the walls – one, a portrait of a baby with a chubby face and a full head of brown curls; the next, a picture of the same baby sat on my future self's lap. The baby became progressively older as I moved down the hallway until eventually a black-and-white shot showed him holding a skateboard, aged nine or so. Who was he, I wondered? My heart fluttered as I recognised a face in another picture – my sister Simone, albeit a lot older since the last time I saw her. Each picture sparked a question, but the one that circled my brain insistently was – what if I'm no longer in 1992 anymore? Could I really have woken up in the future?

Amid the confusion, a name and telephone number popped into my head. I picked up the black phone I'd spotted in the corner of the room and dialled, but I didn't recognise the chirpy voice who answered. Nevertheless, I couldn't stop myself sobbing down the phone to her; I told her that I didn't know where I was, who she was and what was happening to me.

Fifteen minutes later, the same woman arrived at my door and, although I didn't recognise her, her look of concern reassured me enough to let her in. Katie – a friend I'd apparently known for years – remained calm and collected. She told me everything was going to be OK, but I could see the worry in her eyes as she took a small black box from her pocket – something I later learned was a mobile phone – and rang my sister Simone, who arrived soon after. They made me a drink, sat me down and explained that I just needed rest, that I was tired, overworked and that everything would make sense once I'd calmed down. They also offered to look after Leo, my son, who'd been sleeping upstairs the entire time. That accounted for the baby pictures, but didn't explain the absolute void of memory about my having a child. I spent the rest of the day curled on the sofa, crying over the confusion of it all, and for all the things I believed I'd lost – school, even my GCSEs, my best friends, evenings in the park and the comforts of home. I was still Naomi, but I certainly wasn't in Kansas anymore.

Despite Katie and Simone's assurances that everything would click into place, when I woke up the following morning, I felt more lost than ever. Simone took me to the doctor, who diagnosed me with transient global amnesia (TGA), brought on by a period of severe emotional stress. But I'm 15, what do I have to be stressed about, I thought to myself. Simone explained that I'd been through an emotional break-up on top of studying for university exams. I'd also had a stomach virus and tonsillitis. Transient global amnesia is almost a coping mechanism, which causes your episodic memory to shut down. While my semantic memory remained intact, meaning I could remember how to drive and regularly used phone numbers, years of my emotional memories had disappeared. I had prolonged TGA, for which there was no treatment. The doctor told me it could take anything from four weeks to eight months for my mind to root itself back in time – all I could do was wait.

My doctor insisted I didn't read newspapers, watch television or force myself to remember – my memory had to return naturally. But like any petulant teen, I couldn't help myself and curiosity to see how the world had turned out got the better of me. It was mortifying – digital television appeared almost cartoonish in comparison to analogue, and reality television, which seemed to be on every channel, was a complete enigma to me. The only Bush I'd heard of was George Senior and my sister had to painstakingly explain 9/11, 7/7 and the "war on terror". She described the increasing technological, biological and psychological threat to the planet and how it was Muslims rather than the IRA who were the new supposed threat to Western stability. Facebook, recycling, internet shopping... the list went on. I was dumbfounded, but learning about my personal history would prove to be even harder to swallow.

The 20 years' worth of diaries and journals I'd kept opened a window in my personal past and revealed the landmarks on my road to adulthood. I was a single mother and had never been married. I'd had a 13-hour labour and Leo was born in water to the sound of Alanis Morissette. I used to have my own successful holistic therapy business and was studying for a degree in psychology. I could also bake a fabulous lemon drizzle cake. I read in awe, but my 15-year-old self could not quite digest that this was the adult I'd become. I thought I'd have conquered the world by the time I reached 34. I had seen myself travelling the world, working as a successful journalist, writing books about my adventures; or a doctor of medicine healing sick children in Africa. It was hard not to feel disappointed that I hadn't accomplished either of those things and that I didn't live in a mansion having made my fortune.

With a lot of support and reassurance from my family and friends, it took eight weeks for my mind to settle itself firmly back in the future. I had my first flashback three weeks after the onset of the amnesia and they continued for another five weeks, until my memory was fully restored. My therapist suggested that I had suppressed a lot of my returning memories because initially I was disappointed in how my life had turned out and it was easier to remain in denial. When I eventually felt safe and secure and began to accept the future I had woken up in, then my memories started to return.

People often ask how I coped with the fear and uncertainty, remarking what an awful thing to have happened to me. But as scary as it was, I wouldn't change a thing. I feel privileged to have seen the world through different eyes, 15-year-old eyes. Transient global amnesia helped me to re-evaluate my priorities and put my life back together in a different, but definitely better, way. If anything, a window into our future is the wake-up call we all need.

Interview by Sophie Ellis

Naomi Jacobs has written a novel based on her experiences, as yet unpublished

Transient global amnesia

* First reported by Morris Bender in 1956, transient global amnesia (TGA) is characterised by sudden, temporary short-term memory loss and bewilderment. Suffers may also have difficulty accessing older memories.

* TGA, a form of retrograde amnesia, is often brought on by severe physical or emotional stress, physical exercise or sexual intercourse. Some experts also suggest a correlation between TGA and patients who suffer from migraines, epileptic fits, and cerebro-vascular disease.

* TGA usually occurs in middle-aged or older patients. Statistics show most sufferers are between the age of 56 and 75.

* An episode of TGA occurs spontaneously, with attacks normally lasting several hours. Prolonged and permanent memory loss is rare.

* A defining characteristic of TGA is that the sufferer repeatedly and methodically asks relevant questions using the same expression and intonation.

* A TGA sufferer maintains her or his semantic memory – the long-term memory responsible for retaining knowledge about the world, the meaning of words and objects and learned and repeated skills such as the ability to drive.

* A person having an attack of TGA has almost no capacity to establish new memories, but otherwise appears mentally alert and lucid.

* The sufferer will often become aware of their memory loss, and this realisation is usually accompanied by emotional stress and anxiety.

* TGA often correlates with precipitating events, which can occur hours, days or weeks before an attack. Common examples are exhaustion due to overwork or money worries.