Dave Bonta's poem reads like a run of bad omens strung together, and the speaker seems unsure whether they mean anything. It opens with a small, physical moment: a fall on the ice, at a house number, 666, that carries a famous association with the devil. From there things drift into the strange. The "wrong bed" being "ours" suggests a relationship that feels off, settled into something that doesn't fit, and "a long rust" gives the sense of slow decay.
Then the poem personifies tomorrow, who arrives as a woman and announces that she is poison. The future, in other words, offers no comfort. The last lines turn to the title's idea: a sign, we're told, is "the meaning of a sad god." That could mean that omens are only what a gloomy, distant deity leaves behind, or that we read doom into things because we feel abandoned.
The mood is uneasy, cold, and a little darkly funny. The speaker feels shaky and fatalistic, watching for signs while doubting them.