The speaker looks back on a time before the worst was known. He raises a glass, it seems, to the sun and to a "body of water," a pair of images that feel warm, generous and alive. Set against them is himself: dirt, rot, wandering, idleness. The contrast is stark. Nature looks bright and flowing, while he describes his own condition as decayed and aimless.
The key turn comes in the last stanzas. The doctors haven't yet declared him "past recovery," so the illness is still small, and the speaker says it would be bad form to "make a show" of it. That restraint is the heart of the poem. He drinks, drifts and keeps quiet, half-aware of what is coming. The mood is wry, subdued and tender, with a calm that carries an undertone of dread. The title suggests this is a quiet beginning, and the poem judges the speaker's silence with neither blame nor drama.