Make sure you lengthen your stitch. I like to lengthen mine to 3, I normally piece at 2.5.
I also like to use 505 spray to hold the layers together. If you do, remember to wash it afterwards to remove all the chemicals.
You don't need binding when you use fleece - it's tougher than any binding. Just pull it to the front and hem it down.
I posted a tutorial on how to do this and have flat mitered corners.
http://www.quiltingboard.com/tutoria...t-t217971.html
Or you could sew the top and back together (right sides together) leaving an opening and then turn the quilt and do a topstitch all the way around, then a tacking stitch every few inches to hold the layers together.