Hey, Carina, long time no chat! :) Hmm...I think what's "wrong" with this piece is the fact that it is what I call a frankenpoem. It looks like a story (albeit a really short one), but the language makes it sound like a poem. There's nothing really wrong with it (even if it makes me a little worried about you :p), but arranging it into a more poem-esque format might make you feel better about it.

I didn't see much wrong with it. The ending felt a bit rushed but the last sentence saves that. It was a really interesting short story.

The "monster on my shoulder" concept, huh? Actually, when I saw this I was reminded of a song by Jethro Tull, Beastie...

Anyway, let's see here...One thing you could do try is making the sentences smaller and end them abruptly. Space the sentences out, it gives...character? to the piece. Gives out a better feel to the reader of what it is you want to say to them that way.

And don't worry if it's small! I've seen more extensive works that are horrid.