Dave Bonta's short poem is about being sick with a cold and fever, and about the odd patience that illness forces on you. The opening lines treat the two symptoms as awkward companions, "odd bedfellows," which gives the poem a wry, slightly amused tone. Then it turns to goldfinches, which in autumn lose their bright feathers and settle into a quieter state. The speaker seems to see their own slowed-down body in that natural cycle.
In the second stanza, the speaker lies "fallow," like a field left unplanted to recover. The virus is described as something that "slipped in / under cover of affection," which suggests it may have been caught from someone close. Now it is fading, "withering in the ditch." The mood is calm and quietly humorous. The speaker doesn't seem angry or miserable, just tired, accepting, and willing to wait while the body heals, much as the seasons do their own work.