It seems a shame to say so, but the hardest part of being a writer is not the long hours of learning the craft, but learning how to survive the dark nights of the soul. There are many such nights, far too many, as you will discover. I hate to be the one to bring you this news, but someone should.
Part of the deal of having a soul at all includes the requirement that you go through several dark nights. No soul, no dark night. But when they come, they have a surprisingly creepy power, and almost no one tells you how to deal with them…. In these nights you confront your own doubts, lack of self-confidence, the futility of what you are doing, and the various ways in which you fail to measure up. Feelings of inadequacy are the black-lung disease of writing. These are the nights during which the Fraud Police come knocking on your door…
To be a novelist or a short story writer, you first have to pretend to be a novelist or a short story writer…
You sit down and you pretend to write a novel by actually trying to write one without knowing how to do it. (It is clearly not a rule-governed activity; there are only rules-of-thumb that sometimes work.) As you pretend to write your novel, you learn, if you’re lucky, actually how to do it. You learn this intuitively. After you’ve learned how to do it, you proceed to write another novel, and, if you’re lucky, it turns out to be a real novel.
Source: Quoted from “Full of It” by Charles Baxter from the anthology Letters to a Fiction Writer