In just three lines, the speaker describes burying a friend and then, almost in the same breath, feeling homeless. The odd thing is that the speaker isn't literally without a bed. The poem says "I think myself one without a bed," which suggests a feeling rather than a fact. Losing someone close seems to have knocked out a sense of shelter or belonging.
The image of "the green / bone of the day" is striking. Green suggests grass, life and growth, while bone suggests death and what remains after everything softer is gone. Putting them together makes the day feel both alive and stripped bare, as if the funeral takes place in a bright, living world that has suddenly gone hard and empty. The line break after "green" slows us down and leaves a small pause before the word "bone" lands.
The mood is quiet, stunned and lonely. The speaker doesn't explain or cry out. The plainness of the language makes the grief feel more real, and the poem's brevity echoes how little can be said at such a moment.