look inside yourself and seek what you think is most important to you. helping poor or foster kids,helping feed poor people,religion,talking with people that can't leave their homes and are lonely,helping animals,almost anything that helps you get outside yourself and puts your focus on someone or something other than you. volunteers are usually needed at most charitable organisations or libraries,animal clinics,or shelters for adults or young people. I hope these suggestions help you a little.
I was starting to think it was meaningless, until I dedicated my life to making music. If you don't have a hobby to keep you occupied, I think you should do the same. It's a good hobby, and it relieves stress.