Here is an excerpt from “The Antidote: Happiness for People Who Can’t Stand Positive Thinking” by Oliver Burkeman. (I suspect that the excerpt is all you really need. There is a tendency among writers these days to write far too much—"enough to fill a book!"—when a longish article is all that is necessary to get one's point across.)
I post this because I know any number of creative types who suffer from bummout and wish they didn't, and try this and that and the other "method" for gaining happiness. Perhaps we can all relax and let life happen, instead.