For Me was originally a school project but the NSPCC's Childline has turned it into reality.
"I hope that young people now realise they have somewhere to go," one of the creators, Laura Hindle, tells Newsbeat.
The app features a private "locker" area where users get a daily mood tracker and can write down their thoughts.
It also lets users chat with a counsellor.
"I can't believe this app is a reality and is out there for people all over the country to access and use," Laura tells Newsbeat.
