Three short lines, and the whole poem is a complaint: bread is hurting the speaker's stomach. On the surface it's blunt and almost funny. Bread is about the most ordinary food there is, and here it's described with violent words like "tearing" and "apart."
That gap is what makes it interesting. The speaker talks about something comforting as if it were an attack, and the line breaks make the statement land in small, sharp pieces. "This bread is" hangs for a moment before the harm arrives, so we feel the turn from the everyday to the painful.
The mood is raw and tense, with a dry edge of dark humor. We don't learn why the bread hurts. It could be a physical illness or an intolerance, or the speaker might mean something bigger, such as hunger, hardship, or a bitter life that even basic food can't soothe. The poem doesn't say, and that leaves the reader sitting with the discomfort.