Found one of the best thoughts about writer's block written by Octavia E. Butler in an essay titled "Breaking Through Writer's Block".
"If you know your craft, you may even be able to write well in spite of writer's block. What's missing is not your ability to write, but your ability to feel any joy, any passion, any satisfaction in your writing"
I know that feeling well. The words are there, but they all feel and sound like crap to me. Some people tell you to write the crap but for me it just feels wrong and makes me feel sad instead of happy that I've managed to put words down on paper.