The speaker is angry with herself for ruining a day through impatience or careless emotion. She describes the calm hours as if they were a surface she cut and disfigured—"gashed and defaced"—which makes the regret feel physical and sharp. She cannot undo what happened, so she asks to forget, turning to sleep as a small boat that will carry her through the dark into a fresh start.
The mood shifts from frustrated self-blame to something quieter and more hopeful. She imagines the next day as a gift from heaven, "whole as an apple, kind as a friend." That final simile is gentle and childlike: the new day will be unspoiled, round, and welcoming, unlike the one she wasted. There is no guarantee, only a simple wish for rest and another chance.