I was always different to other people. I would have periods of mania and then periods of depression. I think people just thought I was wild.

I thought I was suffering from depression, but it was only when I was 25 and saw a psychiatrist that they finally gave me a label - I was diagnosed with bipolar disorder, borderline personality disorder and post-traumatic stress disorder.

In a way it was a big relief as I always knew there was something wrong. But more importantly the diagnosis led to treatment in the form of medication and dialectical behaviour therapy.

Even with the treatment, I had a few years off work in my late 20s. I would be off for months but then couldn’t cope when I went back. I was on long-term sick leave and I think on my records it just said that I had mental health problems. At that time, although I was comfortable with the label I didn’t want to come out of the closet.

When it all kicked off, the school was not very understanding. I was sent to occupational health, first to prove I wasn’t sick and the second time to prove that I was sick so that they could try to sack me.

I had never had a problem with alcohol, but when I was off sick I started to drink more. After about six months of heavy drinking, I ended up in accident and emergency. I had another breakdown when I was about 30, when I was drinking 20 hours a day. I would drink cider for breakfast and pretend it was apple juice.

After a time in hospital, I decided enough was enough and gave up alcohol. I was back at work a couple of weeks later.

I was really scared about going back. It was walking through the front door that terrified me. I arranged for a colleague to meet me in the car park and walk through the front door with me. She wafted other people away, who were coming to ask me about it all.

I remember going into my classroom, sitting down at the desk and taking the register. I was aware that I was using the desk as a kind of security blanket and I thought to myself: “You’re going to have to stand up now.” So I got up and my knees started knocking, but I asked the class to be quiet and the whole room became silent. From that moment I knew I would be OK - I still had respect.

The old leadership team wrote me off as a basket case. But we got a new leadership team, and by then I had come out about being bipolar. One of the senior leaders is my pastoral care mentor, who I can go to if I need to. It is great, not only that I have someone, but that the headteacher thought of putting someone specifically in place for me. They have been fantastic, and if it weren’t for them - who knows?

I’m now head of languages and I love my job. Through their efforts to adapt to my disability and to meet equal opportunities, they have also had the benefit of me and what I can do. I know that I’m good at it and I’m changing young people’s lives for the better.

My disabilities are actually a useful tool. You get depressive teenagers and who better to know the right thing to say than someone who has suffered from the same condition?

I’m now on 13 different types of medication and take 29 tablets a day. I have a couple of episodes a year when I need to take some time off.

The doctors have got me to the point where my medicine is doing what it can. I don’t really have mania any more. I still have depressive episodes, but they are not as bad as they used to be. So it is not so bad - I can prepare for it, in all aspects of my life.

As told to Meabh Ritchie. Artwork by the teacher interviewed has been used for the Mind calendar, and has been submitted to Kate Swift’s book, ‘Silent no More’. If you have an experience to share, email features@tes.co.uk.