It doesn't suck, I liked it. It conveyed the message just as the poem is meant to. I think you just need to work on the formatting so it's easier to read and make connections between the rhyming words.
She was put in a cage
Yet she did not show rage
She was mistreated and malnourished
Her eyes showed despair
I could only stand and stare
When I bought her freedom
She nuzzled me
It was like she was thanking me for setting her free
She liked to play and wrestle
For it was never a hassle
She would sleep with her head in my lap
For her it was a good place to nap
She taught me how to wine, screech and growl
When we played tug of war with a towel
I was sad when we had to part
She had found a place in my heart
I never knew an animal could show so much love
She might have been an angel from above
Today I learned that she died
Today I cried
I would never trade her memory, no way!
I still think about her every single day.