Wow that poem packs a punch! I can truly relate to this so much.. it's horrible. There's no worse feeling than the feeling of being used.

All I have to say for this poem is to be careful of the words you use, such as:

"Then were not at school,
Your kind hearted and funny

'were' should be we're
'Your" should be you're
I've noticed it in some other places as well, and it makes a big difference lol..

But this was a very good poem. Keep it up!