The speaker wakes up hungover and disoriented, and the poem treats that fog as something close to a loss of self. The opening joke does a lot of work: he "lost the letter I in a card game," so the first-person pronoun has literally dropped out of his sentences. Without it, he describes the world in flat, fragmentary glimpses: scarred sky, laundry on the line, a few colors named like labels.
Then comes a flicker of loneliness ("where is everybody?") and a sense of mental emptiness, with even the light bulb out of ideas. The body is imagined as an old, well-worn book, begging to be read by someone else, and the glow of sun through closed eyelids becomes its gold-edged pages. That image is tender, almost beautiful, which sits oddly against the rough mood around it.
The tone is wry, tired, and quietly desperate. The closing line admits the joke's real cost: it would be easier if he still made sense.