The speaker begins with a puzzling complaint: their work isn't done the way they could do it, or the way they would choose to. It feels borrowed, or shaped by someone else's terms. The odd phrase "work myself" hints that the speaker is somehow working against their own self, or that the job asks them to be someone they aren't.
Then the poem shifts to night. The speaker goes through "a little private door in a wall," then "a narrow place," and finally "into a box." Each step gets smaller and tighter. Judging by the imagery, this could be a bed, a home, or even a coffin, and the poem leaves that open. What comes through clearly is a sense of confinement. The mood is quiet, weary, and a little bleak. Work doesn't leave room for the speaker's real abilities, and rest seems to offer only another enclosed space. The plain, flat tone makes the feeling land harder, since the speaker doesn't complain loudly but simply describes the squeeze.