"Why me?" Who hasn't gazed up at the heavens and asked that question in a fit of despair? Whether it's facing down a pop quiz or getting dumped the night before prom, it can feel sometimes that the world is conspiring against you. Most of us, though, don't do much follow up. It's more of a rhetorical question that's meant to say "my life just really sucks right now."
The speaker of "Carrion Comfort" isn't content, though, to let the question drop. In fact, this whole poem is his way of figuring out an answer to that "Why me?" question. And the great thing is that, by wrestling with this question a bit, he actually comes to a satisfying answer (satisfying to him, at least).
Before he gets to that answer, though, he has to give himself a pep talk. In the first stanza, the speaker asserts his determination not to give in to despair and end it all. We get a sense of that determination through the sheer number of times he says that word "not" in the first two lines (four, to be exact). This kind of repetition makes him seem like more than just a person who's run out of ways to say something. Instead, he's repeating "not" to himself almost as if he were trying to convince himself to keep going. (Think of the way the Little Engine that Could talked to himself: "I think I can. I think I can. I think I can, etc.")
By the time we get to the second stanza, then, the speaker is moving forward, looking for answers. He realizes that his struggles have left him stronger for the experience. Metaphorically, he's become like a tasty crop, with all the bad, useless bits stripped away: "That my chaff might fly; my grain lie, sheer and clear" (9). He also realizes that his road to self-improvement has been about more than just him. It's been a spiritual quest: "I wretch lay wrestling with (my God!) my God" (14).
That parenthetical note—"(my God!)"—is really telling. The exclamation mark indicates genuine surprise on the speaker's part, as if he's just stumbled onto a profound realization: his despair has tested his faith in God, and now it's that much stronger. In that way, this poem has not taken the typical form in which a poet has a "deep thought" and then lays it out for her reader. In this case, we have a speaker who has been thinking through the poem, trying to piece together why bad things have happened to him. At the end of the poem, he has his answer—and so do we.