Abbie's poem is about a love the speaker can't quite name. She describes one man who pulls her in two directions at once: he makes her laugh while he's making her angry, he makes her love and craziness feel like the same word, and she loves him even while hating him. The repeated "He is the only guy" gives the first four lines a steady, almost confessional rhythm, as if she keeps circling the same stubborn fact.
The speaker feels confused, but also quietly certain. In the last two lines she admits she doesn't understand these feelings, yet she can't think of anything else to call them. "If this is not love, I don't know what it is" (the poem drops the "know") turns her uncertainty into an answer. The mood is raw, honest, and a little exasperated, like someone talking out loud to herself. The plain, simple language makes the feeling seem unpolished and real, which suits a love that doesn't make tidy sense.