A sleepless speaker lies awake listening to rain, a sound that should be soothing, yet sleep never comes. Then the poem turns: the "rain" may not be rain at all. What the speaker hears is thunder, the call of a storm still far away, and the line "It was not raining at all" quietly undoes the opening.
The mood is restless and slightly uneasy. The speaker seems caught between wanting comfort and being unable to find it, and the word "fantasizing" suggests a mind drifting into imagination, perhaps even mistaking one sound for another. Judging by the poem's form, the repeated lines loop back on themselves, so the last line returns to "I listened to the sound of the rain," even though we now doubt it. That circling feels like the speaker's thoughts going round in the dark, never settling. The distant storm may be literal, but it also hints at something unresolved just out of reach, keeping the speaker awake.