Trouble with the internal editor

I just can't seem to turn it off. I can't even tune it out. And it's killing my writing.

Too slow. Too slow. Too slow.

It won't shut up!

Yawn! Come on, when is something exciting going to happen?

As soon as the manuscript comes to mind, that stupid little voice pipes up.

If they (agents) think your last one was too slow, this one is like dragging a brick through cement.

I've tried writing fresh, adding plot elements, cutting, rewriting.

You'll never get an agent off this.

And now, I avoid the entire story -- writing about it, thinking about it, plotting it.

It'll never sell.

What's a girl to do??