I am a good writer!
Look at yourself in the mirror and say it three times. Hell, say it more if you need to. Say it until you believe it.
We have those days where doubt creeps into our minds. We think we are terrible. We think no one will ever like our stories. We wonder if people will laugh at us after reading our words. We hear whispers and think people are saying terrible things; calling us hack writers and suggesting a kindergartner has more of a vocabulary.
Don't allow those thoughts and feelings to stop you.
Look in the mirror and tell yourself you are good. Always keep writing.