A small, quiet scene: someone alone at midnight, eating cold meat, probably standing in a kitchen or sitting by a dim light. The speaker compares themselves to the moon, which is solitary and distant, and the title, "Perigee," the point where the moon is closest to Earth, adds a hint of nearness inside that distance.
The second half shifts into something stranger. An "angel" stands by the door, and its seriousness makes ordinary songs feel wrong. The angel might be a literal presence, a feeling of being watched over, or an image for the weight of the moment itself. The poem doesn't say, and that openness is part of its charm.
The mood is hushed, a little humorous, and a little solemn. The plain meal sits beside something almost sacred, and the speaker seems both lonely and oddly accompanied, aware that even a late, unremarkable snack can feel important.