If you used the same washing/drying methods as you always have then it must have been the fabric. There has been many post about Joann's fabrics. Was this some of the cheaper fabric from Joanns? Did you over dry the quilt? As we can all atest to cotton will shrink over time especially if it is over dried. When I was my quilts , i do not put them in the dryer but rather dry them over a bush outside or lay them over chairs inside.