What makes a poem a poem, hows this one

You know it's kind of sad
The way things worked out
But it's not all lost
There's still a little hope somewhere in here
I'll find it I swear
Follow along and I'll show you the way
Come take a chance on me
It'll be great, you'll see








Does this count as some kind of good poem or is it random lines w/ a constant theme?

Is that what a poem is anyways?

Is there even a constant theme?