I was a geography teacher at a school in Reading. As head of department and senior tutor of humanities, I was well-established in the school and I loved my job. For a number of years I had been visiting osteopaths and physiotherapists about persistent backache. I also began to notice that I was developing a slight left-hand tremor which interfered with my teaching and made my handwriting messy.

Finally, a physiotherapist referred me to a neurologist. I presumed it would just be a nerve problem. I was only 47 so I wasn’t worried that it would be anything serious.

I had a brain scan in June. Two weeks later, the results letter deceptively reassured me I was fine. “You will be pleased to know that your brain scan was normal,” it said. I went to see my doctor for the follow-up. He told me that I had a chemical imbalance, which didn’t sound too terrible, then he added: “You have Parkinson’s disease.”

My first thought was “will I go bonkers?” I had read about Parkinson’s previously, but dismissed it as a condition for old people. My mind started to race through the practicalities of my diagnosis: would I be able to carry on teaching? The doctor’s off-hand manner made light of the reality. It was only as I stood to leave the room and he said “I’m terribly sorry” that it started to dawn on me.

The news had stunned me, but I didn’t know what to do next. No one gave me any further information or comfort. Assuming it was a routine appointment, I had gone on my own. I can still vividly remember the icy-blue walls of the empty hospital corridor. I was numb with shock. In a daze, I drove home to tell my husband.

I needed to clarify the truth about my condition so I could prepare for the future. I made another appointment at the hospital, where I was told I could expect “five to seven reasonable years” before things started to become difficult.

I hadn’t told the school about my health concerns. From initial symptoms to my diagnosis, Parkinson’s had crept up on me. I wanted to continue teaching, although I reduced my working hours. To disguise my hand tremor, I would teach sitting down where my hand could be hidden under the desk, or put my hand in a pocket. I tried to introduce my illness to my pupils gradually. I needed to tell them so that they knew the tremor was beyond my control.

The first three years after my diagnosis were the most difficult. I was on the mildest medication, which meant I felt unable to control my actions. My sleep, balance, shaking and handwriting were all affected. I found it difficult to accept my “sick-person” identity.

Then I was started on a course of stronger medication that controlled my tremor more effectively. However, my sleeping problems worsened and I would only sleep four to five hours a night. I would experience sudden sleep attacks in the day, sometimes mid-conversation. Eventually I made the difficult decision to leave teaching and seek early retirement.

I miss the classroom, but since 2008 I have been writing geography textbooks. I am able to keep in touch with my subject in a way that suits my lifestyle.

I also have a new outlook on life since my diagnosis. My new priorities place family and friends at the centre. Ten years since my diagnosis, it is true that things have become difficult. However, I am better at managing the effect of Parkinson’s on my everyday life.

Briony Cooke was talking to Emily McQueen. For information on Parkinson’s, go to www.parkinsons.org uk. If you have an experience to share, email features@tes.co.uk.