The speaker seems to be taking stock of what it means to live in a body and still try to be content. The opening image, the body as a "horse" from which we make "filth and love," treats physical life as something both messy and tender. The next lines sound dutiful rather than joyful: the speaker feels "obliged" to think themselves happy, which hints that happiness here is something worked at, not simply felt.
The middle of the poem widens out. Winds that exist "only to entertain us," and voices buried in "one infinite chapel," suggest a world that is beautiful but also a little like a tomb. The window that is "better than an absence" reads as a small, practical comfort: some opening, some view, is better than blankness.
The ending is blunt. Being awake brings anger, and sleep means giving in. The mood is wry, restless and quietly stubborn, caught between resignation and refusal.