I have had this same problem with a flannel baby quilt. Although I purchased the fabric at a reputable quilting store I did note that the weave of the fabric was quite loose, and should have known better than to just do a 1/4 inch seam allowance. I have learned my lesson and make sure that the weave of the fabrics I use is a good tight weave.
For mine there was no solution, but I sewed beside each and every seam and and he dragged it around till it fell apart. I think it was the fabric, not the quilter which caused the problem.
Congratulations on the completion of your first quilt. Sorry it didn't hold up really well. Looks very pretty.
amh