I’m just not happy?

You sound a mess. Take a minute a re-read your question or sad summary. Your answers are in your own questons. If you want to get up and go somewhere, then get up and go. If you feel like you should be doing more with yourself than figure out what that would be and go do it. If your friends are young and immature find older and new friends. And stop caring what people think. The reason you care so much is because you lack loving your self. I don't know you, but based on your summary, you paint, play guitar, go to a private school (which probably means a good education) and is emapthetic. Sounds like you have a few things going for you. Focus on how amazing that is. The more you focus on the cool things about your self you will start to forget the bad. Cheer up!