Okay, so I'll start out saying I've read poems like this a thousand times. That's okay, but there's ways to make it so much more catchy;

" No I'm nothing to myself...
nothing to myself...
when I'm nothing to myself"
Try jazzing it up a bit, like;
"No I'm nothing to myself...
not a thing to myself...
when I'm nothing to myself."

It's not as expected and empasizes a bit more.

some people say I is too much, not to use it at all.. I don't agree with that. But you can make a poem too wordy by using tiny words way too much and over and over.
The first stanza is bad with the I's, one way to make it tons better is;
"I often sit and I wonder why"
Try;
I often sit and wonder why

Or
"you wanted to make it you and i"
you could do;
you wanted us to make it.

I personally think the first one flows better, both changed is just fine. but the first is by far the best, for me.

this is a good poem. i don't vote unless i vote a 3 or higher (for future reference) because i don't want anyone's scores to be brought down significantly.
i am giving you a 3 though, so i will vote