There’s a phrase, “sitzfleisch”, which means just plain sitting on your ass and getting it done. Just showing up for work. My uncle Raphael was a painter, and he used to say, “If the muse is late for work, start without her”. You have to be there. You have to be there, and do it, and grind it out, even when it is grinding and you know you’re probably going to rewrite all this tomorrow.
Writing has nothing to do with publishing. Nothing. People get totally confused about that. You write because you have to - you write because you can’t not write. The rest is show-business. I can’t state that too strongly. Just write - worry about the rest of it later, if you worry at all. What matters is what happens to you while you’re writing the story, the poem, the play. The rest is show-business.