At the end of the day, when you’re exhausted and doubting yourself and unsure, simply believe.
Believe that your writing will better the world.
Believe that your writing will better you.
Believe that your writing will stay after you—long after you’re gone and dead and turned to dust—and will continue doing your work of making the world better.
What other reason do you need to keep writing?
Your belief will carry you through your moments of dread, doubt, and despair.