1: You sang this in a high falsetto. Your voice would be better served with a more natural key for you. That being said, your tonality is still pretty good. I realize asking you to transpose all of that into a lower key is a bit much to ask.
2: Drums. Yeah, I said it. You have timing issues... not too bad, but drums are your friends, and practicing with a drummer will make you tighter. It will take that uncertain feeling out of your performance, I promise. I refuse to suggest metronomes regardless of how useful they may be; they still don't replace drums. Even bongos.
Overall, I'm impressed. Did you sing and play this simultaneously? If so, good job.