When I was doing the training on how to resuscitate and use the defibrillator machine, I thought that it would feel good to save someone's life. But when it came to it, I couldn't work out why I was feeling so horrible - that was the thing that surprised me the most.
The incident happened last November. It was about 3pm, when all the children were getting ready to go home. One of the teaching assistants came into my classroom to say a parent had collapsed outside.
I knew Janyne and her husband Martin quite well. I'm the reception and Year 1 teacher and their daughter had been at Frettenham Primary in Norwich for about five years. They lived next door to the school and it was as Janyne was walking to collect her daughter that she collapsed outside the school gates.
One of the other parents was already administering CPR (cardiopulmonary resuscitation) and when I saw that I didn't hesitate to turn on the defibrillator that the TA brought along. The machine assessed her condition and it told us that a shock would be a good idea. I then administered CPR.
It was very strange, but it was like the old cliche - you don't think about what you're doing. I was about to do a secondary analysis when the paramedics turned up and took over. It probably took them four or five minutes, but it felt longer. She was blue and they were concerned that she may have been deprived of oxygen, so they were in the ambulance for a long time.
Once the ambulance had taken over, and I had taken a step back, that was when all the thoughts started happening inside my head. I didn't know whether she was going to make it or if I had done the right thing. When you are not so directly involved, you then realise how serious the situation is.
The hardest time for me was probably a couple of days afterwards when it really hit home. It did get me down. The adrenaline keeps you going at the time, but then all the what-ifs come into your head. Every time I closed my eyes to go to sleep, I could see it all happening again.
Everyone was patting me on the back and calling me a hero, but I felt a bit like a fraud. I also received deeply felt thanks from her husband and her parents, which was very humbling. But I just wanted to say - it's not me, it's everybody.
If the classroom assistant hadn't come out with the defibrillator, I wouldn't have been able to do it. The TA also kept all the pupils inside the classroom, including the victim's daughter, so they didn't know what was going on. Another teacher went to the front of the school to divert the bus from the high school that would usually stop at our school. All I did was follow instructions on a machine.
It took weeks as opposed to days before we knew she was going to be OK. She had short-term memory loss in hospital, but her memory came back eventually. It wasn't until she was finally out of hospital, and I saw her and she came and gave me a hug, that I felt a lot better about it all.
Now when I look back at it, I feel proud of the fact that I had such an impact on someone's life, but it took me a while to get to that.
The relationship I have with the mum is the thing that has changed the most. There is an unspoken bond there now and I think she feels that, too. There is an acknowledgement that we have been through something that doesn't happen every day. And I know she is forever grateful for that.
David Board received training from the British Heart Foundation and the Resuscitation Council UK, who want every young person to leave school with the knowledge and skills to save a life. www.bhf.org.ukels. He was talking to Meabh Ritchie.