Teens face a lot of pressure-grades, friends, parents, trying to fit in. It's completely normal, even if you can't pinpoint the exact reason. However, if you start to feel withdrawn, have problems at school, become extra sensitive or aggressive and angry your depression might be getting serious.
If you feel this way, tell your parents, there's superior help out there.
Being a teen is a trying ordeal, spending time to yourself is sometimes a great escape from pressures. But if you become too withdrawn you may be slipping in too deep.
Former teen who had depression