Are you here to change the world?  It is already altered by your presence.  You can relax now.  2000 years ago, a man walked the earth and changed the world, but he did not completely heal it, and neither will you.  It is all a process, this thing called Life.  It is ongoing.  Healing takes place, but so does hurting.  You are here to be.  By your very presence, you shine.  Focus on your own light and shine as brightly as you can.  Enjoy the process.  Know that all is in order and you do not have to do it all.  You cannot do it all.  You cannot heal the entire world, nor are you supposed to.  Just be.  Just shine.  Just love.