Keep writing.

The voice in your head will keep doing its job. It will keep telling you that you are not in the right state of mind, that you should come back later to this, that tomorrow will be better somehow.

But if you keep doing your job, if you simply take it as a physical exercise of moving your fingers over the keyboard, instead of an emotional one, you will get one version out. And that's a place from where you can start to make things better.

Whatever it is that you want to do but are unable to get started, sit with a blank page and keep typing. The more you type, the more are the chances that you will start moving forward.