Anyone who has lain awake at night while their mind replays the same worries will recognize what's happening here. The speaker wants one simple thing, sleep, but their thoughts refuse to cooperate. The poem opens with a plain wish, then the word "however" and the trailing dots show the plan falling apart almost at once.
Most of the poem is questions: "Why can't they stop?" "Why do I have to remember?" The speaker isn't really expecting answers. The questions loop and circle, much like the thoughts they describe. The last two lines bring a quiet defeat. The speaker is "still awake" and reduced to "begging" the thoughts to stop, which suggests they have no control left. The poem never says what the thoughts are about, though "remember" hints at something from the past. The mood is tired, helpless, and a little desperate, and the short, bare lines make the exhaustion feel real.