The speaker wakes up cold and stiff, then watches everyone around them react with horror: coworkers stare, the boss goes pale, and a date vomits and runs off. Only when the speaker checks a mirror does the cause appear, a pale, grotesque, corpse-like face. By the end, the speaker is left asking, "I'm a corpse, aren't I ??"
The tone is oddly flat and darkly funny. Comparing stiff limbs to "terrible restaurant bread" is a joke placed right beside something grim, and the plain, matter-of-fact way the speaker narrates makes the situation feel more absurd. But the humor slips as the day goes on. The speaker feels "a heavy sadness" and wonders why people treat them like a freak, which gives the poem a real sting of loneliness and rejection.
You could read it literally, as a strange comic story, or as a picture of feeling numb, drained, or invisible to the living. The poem's last question is unsettled, and it leaves you unsure which reading the speaker believes.