Everyone feels sad or lonely, or angry now and again, when I wrote that I sure did feel that way in the moment, and it was just a way to express it. Poetry is a kind of expression where it's not supposed to make logical or grammatical sense. If you felt sad when you read the poem, then it communicated what it needed to communicate. If it caused you to introspect for a moment an think about your internal world, then it did its job.