The poem sets two worlds side by side. On "the happiest of them all," the speaker sees a bright, festive scene: white-covered ground, hopeful faces, people dreaming that their needs might come true. The title suggests a holiday, though the poem never names one. Meanwhile the speaker is cut off from all that warmth. Fog, dim light and cold darkness "subdue" their image, and their body aches and tears.
What follows is a string of apologies. The speaker says sorry for being less than the others deserve, for being weak, for giving up so quickly, and even for thinking about a fight they feel they can't win. They call themselves fake, like "cheap Nike," and sink lower than the ground itself.
The ending is the darkest part. "I shouldn't have tried" and "shouldn't have lived this life" suggest deep hopelessness and possibly thoughts of ending life. The mood is heavy, guilty and lonely, made sharper by the cheerful setting it contrasts with.