The title, "Post mortem," sets the scene: someone is dead, or imagining being dead, and looking at what remains. The opening line is strange and quietly funny. Tomorrow has "missed" the speaker, as if the future walked past without noticing the body. There is no pain here, only a flat, stunned calm.
The images that follow are odd and a little darkly comic. The dead are "a poor dinner," so not much use even to whatever might feed on them. They lie "in a box like letters from death," which suggests messages that have arrived but can never be answered. "Counterfeit sleep" is the sharpest phrase: the sleep looks real but isn't, and the "strange hair" shows how unfamiliar a body becomes once it is no longer alive.
The ending turns tender. "Her face the same face as my soul" suggests that the person the speaker loved was so bound up with him that her face stood for his inner self. The mood is cold and detached, then suddenly intimate.