'I mainly cut myself but I also scalded myself, burnt myself with lighters and scratched my skin.
'I was secretive about it - I'd do it under my knickers so that if I had to get changed in front of people they wouldn't be able to see anything.
'I'd been depressed and anxious and I was starting to get problems with food. Seeing blood would reassure me that I was more in control.'
Hearing about experiences like this has encouraged Sophie Clarke to start a campaign with Fixers to educate parents and teachers on self-harm.
She spoke to ITV News Anglia about her project on March 9.
With Fixers, she has created a booklet explaining the signs of self-harm people should look out for.
The 18-year-old, who lives in Framlingham, Suffolk, says large numbers of young people are affected by this issue.
'Most teenage friendship groups know someone who self-harms,' she says.
'My form of self-harm wasn’t visual. I punished myself emotionally not physically. I know that people who do cut themselves feel alone and isolated.
'There are people self-harming every day, every hour, and they don't have the help they need. I don't believe that parents and teachers know enough about this,' she says.
Sophie's campaign is supported by sixth form support tutor Ashton Harewood.
He says: 'I really do believe Sophie's project is worthwhile.
'I’ve been working with young people across Suffolk for around seven or eight years now and in that short space of time there has been a large increase of self-harm cases.
'It’s important that parents try and understand the reasons why it's happening and how best to support their child - without feeling like it’s a personal failure or some kind of attention seeking behaviour.'
To find other resources on this topic, and watch Fixers films, click on the image below.