Falling asleep is the whole story here. The speaker lies down, the light goes off, and they know it's late, well past the time they meant to be asleep. But sleep doesn't come right away. Their body is in bed while their thoughts drift off into space, wondering about purpose and who they might become.
The mood begins restless and slowly settles into calm. Early on, there's a gentle frustration in being awake when they shouldn't be. Then the poem softens: the sheets feel safe, the heart slows, the breathing deepens, and the walls seem to fade as the eyes close. The repeated phrases ("to sleep, to sleep," "in time, in time," "I sleep, I sleep") work like a lullaby, and the short, steady rhymed lines feel like rocking. By the end, the speaker stops worrying about the hour altogether. Sleep arrives, and the final line, "I sleep at last," reads as quiet relief.