There's a symptom of depression called Anhedonia, and what that means is when you lose interest in other activities that you used to enjoy. When you're in adolescence, it can happen in a few different ways: maybe you've lost interest in those activities because you've outgrown them and you want to try on something new and that's obviously not a problem. But if you feel like you wish you wanted to go dancing again, dancing still like you used to, but you just don't - that's more along the lines of Anhedonia. What you want to do is if you've lost interest in things like that, make sure you get enough sleep. Make sure you try exercising even if you don't want to - it might spike your endorphins so that you can start getting back into the habit again. And if that doesn't work, then talk to your parents and perhaps see a therapist or a psychiatrist because that does lead to more along the lines of depression.