The speaker is hurt by someone who once mattered deeply, and the poem is built around their failure to make sense of it. Each stanza begins with the same line, "I can't explain," and then names a different physical or emotional reaction: a punch in the gut, a held breath at the sound of a name, rage in the blood. The repetition feels like someone circling the same wound, unable to stop touching it.
What stands out is the mix of feelings. There is anger, but also a lingering pull, since the person's power over the speaker is "as strong as it was from day one." The betrayal hasn't broken that hold, which seems to be part of the pain.
The final line, about a mirror shattering and echoing down an endless hallway, closes the poem with a striking image. It suggests something broken that can't be repaired, and a hurt that keeps reverberating. The mood is tense, raw, and unresolved.