I was 23 and studying to be a teacher when friends noticed I was slurring my speech and losing my balance. My GP gave me iron tablets for anaemia, even though no blood tests were taken; I was also told I must be depressed, even though I wasn’t asked about my mood.

I found it hard to do even the simplest tasks. I lost sensation in my fingers, making fiddly things such as doing up buttons difficult. I spent a lot of time in bed. My concentration slipped and it felt as if my brain was slowing down. Language, which had been my passion, began to recede.

I was desperate to find an answer, so went to see a private neurologist. After countless tests, I was finally diagnosed with multiple sclerosis. It was a shock, but I was relieved finally to find out what was wrong with me.

I was prescribed Rebif, which is often used to slow the damage to the nervous system caused by MS. I had to inject it three times a week.

Soon after my diagnosis, I decided to give up teaching, the only career I had ever wanted to pursue. It was a devastating decision, but I couldn’t see an alternative. My husband, then working as an IT manager, took time off to take care of our two children.

Over the next seven years, my symptoms didn’t worsen, but they came and went, which is typical of MS. I was up and down; when I felt stronger, I presumed the drug was having the desired effect.

Eventually, I felt well enough to take on a job as a teaching assistant. I was glad to be back in education, but living with the condition meant there was always a sense of loss that I was never going to live my dream of being a teacher.

Then, 13 years after my initial diagnosis, the doctor called me in for a routine hospital appointment. He told me that because my consultant had retired, they had reviewed all of his cases. Then he told me very matter-of-factly that I did not have MS.

I was furious. I pictured all those years bed-bound, the injections, the impact on my children, husband and career, and all for what? In a haze of incomprehension, I demanded answers. The doctor’s replies were vague. He suggested that my symptoms may have been caused by a lack of vitamin D, which a simple blood test would have confirmed and a heavy dose of supplements would have fixed. There was no apology.

Many people, including that doctor, felt I should have been relieved or even ecstatic at this news. They encouraged me to think of the life I had ahead of me, but all I could think about were those 13 years of my life lost to a disease I didn’t have. Not only had I given up my career, but I felt I had let down my family, failed them as a mother. I had site sores from injecting myself for seven years, and no one knows if there will be any long-term effects from taking the drug for so long.

I complained to the hospital trust, but no action was taken, despite talk of hundreds of similar cases. I went to a solicitor to try to sue, but because it was a hard case to prove, I couldn’t get legal aid.

After that appointment, I realised that nothing bad was going to happen if I stopped taking so many precautions to guard my health. Accepting that my life was no longer defined by the illness had the biggest effect on my recovery.

I started the journey back to becoming a teacher and completed a four-year Open University degree in two years while juggling family life with full-time work. I wanted to prove my worth and felt I had to catch up on the time I had lost in my 20s. Suddenly, it was as if everything I’d built up around me didn’t quite fit any more. I left my husband to start a new life.

I’m 43 now and I feel physically and emotionally stronger than ever. I’ve just started a new job as assistant head in a large primary school. The medical profession never did find out conclusively what was wrong with me. Luckily, I am rarely ill these days – I avoid going to the doctor, and will always question everything they tell me.

• As told to Kyra Hanson

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