Ralph Keyes' The Writer's Book of Hope: Getting From Frustration to Publication is an absolutely superb book that I highly recommend to any writer. As a writer staring at a first draft for my fifth book that at this stage seems perfect for the Trash folder on my Acer laptop, I am in need of some TLC and am finding it in this book.
In the first chapter titled The Essential Ingredient he writes:
"The hardest part of being a writer is not getting your commas in the right place but getting your head in the right place. Where help is really needed is in the area of countering anxiety, frustration and despair."
He cites Stephen King's On Writing: A Memoir of the Craft, a book I read a few years ago and recommend. King said, "Confidence during the actual writing of this book was a commodity in remarkably short supply. What I was long on was physical pain and self-doubt."