'I've been mentally ill almost my whole life'
6 November 2013 Last updated at 07:51 GMT
For as long as she can remember, Jessica has been mentally ill.
The 16-year-old suffers from panic attacks and depression and says it's had a huge impact on her life.
She's now volunteering as a young mentor for the Mindfull website, giving advice and support to other teenagers about mental health.
The site is being expanded so that anyone under 26 can join.
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