Journaling.
To most people, it sounds like a challenge, and a complete waste of time. The thought of taking time out of your day to jot down some thoughts seems ridiculous, and so not many people take the time to journal. However, doing this, taking the time to write about your day, and how you're feeling, it isn't as annoying and time-consuming as it sounds.
Whether you like writing or not, journaling is something I always recommend. There are no real words that can describe how it feels to get out everything plaguing your mind onto paper, without the fear of being judged for it. It's a great way to blow off steam; it's a great way to understand yourself better, and also a fun way to keep track of the many memories of your life, some that you probably won't remember have happened.
A lot of people refuse to keep a journal because of the commitment. Which is silly. Journaling doesn't have to be work; it can go with your schedule. There is no pressure to write. You could only write when you're angry; you could only write when something interesting has happened; you could do and write whatever you want.
Journaling will help you feel better about yourself; it will help you figure out how to solve your problems, and it will always be there as a great outlet. Writing your feelings down on paper is worlds different than verbally telling them to someone; the paper can't talk back; the paper can't judge you, anger you, make you feel worse about yourself.
And when you're much older, reading back on your stupidity will always make for great entertainment.