Finish every day and be done with it. You have done what you could; some blunders and absurdities crept in; forget them as soon as you can. Tomorrow is a new day; you shall begin it serenely and with too high a spirit to be encumbered with your old nonsense. ~ Ralph Waldo Emerson
Such a beautiful, inspirational life philosophy - which, I think, can also be applied to writing. We should let old disappointments, rejections, self-doubt, even writer's block, drift away with the past. There's no reason to waste even another moment dwelling on them. Onward and upward!