I said that to a friend of mine the other day.
We were having a conversation about writing and the various pitfalls and pleasures associated with the act.
Then the words came out of me, "Everything I write is crap."
My friend looked at me, dead in the eye, then nodded and said, "I know exactly what you mean. But you're still writing. Right?"
"Yes," I admitted.
"Then don't worry about it. It'll click when it happens."
Then we went back to our conversation which segued into a discussion of PhotoShop and the various e-publishing platforms.
It was nice to commiserate with someone, to be self-critical and not get a polite, knee-jerk response of, "Oh, I'm sure it's not!"
Sometimes, only other creative people will understand what you're going through. Only someone who paints or writes or composes music will understand that sense of ennui and loathing your own work produces within you.
Not because your work is that bad, but because it's not as good as it could be.
When you realize that this is happening to you, that this is how your work makes you feel, the best advice I can give is to take a break. Put down the pen, turn off the laptop, throw the banjo out the window.
Put it down, walk away and take a little time doing something else. Then go back to your work at some future time. Repeat as necessary.