Depression
Depression is more than simply feeling unhappy or fed up for a few days.
Most people go through periods of feeling down, but when you're depressed you feel persistently sad for weeks or months, rather than just a few days.
NHS
These overviews provide additional information on depression in adults and children.
Depression in Children and Young People
Supporting a child/young person
NHS NELFT - Children's and Young People's Mental Health Service (CYPMHS)
Support for children and young people in Kent with mental health difficulties.
https://www.nelft.nhs.uk/services-kent-children-young-peoples-mental-health
This includes how to refer for support.
Mind
Additional information and support