The speaker's day is built from a plain sequence of actions, each one starting with "After that." Letters arrive, carried by an ox and a dove, which makes the mail feel half ancient, half fairy tale. They are "good as oysters," a odd and pleasing comparison that suggests the letters are a treat, something savoured and a little luxurious.
Then the speaker writes back, sleeps, walks, and finally sits. The poem gets quieter as it goes. The long burst of letter-writing gives way to rest, then to a walk where the speaker is "talking," perhaps to themselves, perhaps still carrying on the conversation the letters began. The last line is the shortest and the stillest: just "I sat."
The exclamation "God forgive me!" is the one flash of feeling. It hints at a small guilt about sleeping in the middle of the day, as if rest needed an apology. Overall the mood is calm, contented, and slightly whimsical, a day winding down to silence.