The speaker talks about debt in a strange, slightly haunted way. The debts they have "shed," the ones they thought they were rid of, don't vanish. Instead they nibble away at the speaker, "one little bit" at a time. Debt here seems to mean more than money; it could be any obligation or worry that lingers after you try to put it down.
The creditors arrive wanting "an account of my general fear," which turns the whole thing into a kind of bargain with anxiety. The speaker's only currency is writing. Calling themselves a "broke bard," they turn that fear into "more useful letters," which can mean words, poems, or even letters in the mail. The poem suggests that making art is how the speaker pays up.
The mood is wry and tired, with dark humor under the worry. There's a small sense of defiance too: the speaker is losing pieces of themselves, but still has something to trade.