Hi,
Congrats on picking up on some signs. years ago, teenage depression was not acknowledged very often. Families would dismiss the behaviours as "ah... the teen years" or "teens are difficult" etc. That led to many people relapsing in young adulthood or later, sometimes over and over again. What some studies have come up with is that the earlier that depression is recognized and treated, the better chance of it being a "one time only" episode. It would be worth your while to seek help from a professional now. If you are suffering from depression and it is treated immediately, you may never have to feel that way again. Take a chance to consult... you have the power to affect your mental health now and in the future. You can do it!