Which form best describes the poem this excerpt is from?
It's a lyric poem. Lyric poems have a musical rhythm, and so we can define a lyric poem as a short poem of songlike quality. The author often explores feelings and emotions in such a poem.
A lymeric is a five-line humorous poem.
A haiku is three-line poem.
A concrete poem is written in such a way that the shape of its words on the page matches the subject/topic of the poem.
So the answer is: lyric poem
