Loom Knit Baby Blanket

My first baby blanket was made on the Boye looms the large one orange, this was the first time loomimg on them.
I made the baby blanket to try my hand at that, I was tired of same stitch scarfs and hats, that being said:
my blanket is longer in the middle by 2 1/2 - 3 inches and still curls at the top and bottom. HELP
what did I do wrong?

I chained stitch on the loom
k1
p1
k1
p1
pkp E wraped pkp tell I got the length I wanted  
p1
k1
p1
k1
cast off using the stretch knit stitch.