I Want To Make A Difference

I want to make a difference in this world. I want to matter to someone. I want to live my life knowing that I have done something good and the whole world doesn't need to know. But I want to cry tears of joy, I want to be moved by something good and productive. I want my life to matter to someone. I want my life to truly matter. What can I do? How can I help? Where should I go? What is my purpose?