Do you mean you washed the individual blocks before you completed the quilt? If so, I can imagine that wouldn't turn out so well. I think even washing a completed top before quilting it would be tricky. I don't mean to sound like "quilt police" by any means. I believe we should do what works for us, but to me, individual blocks can be kind of fragile. We can even stretch them out of shape by ironing too vigorously. So I prewash some fabrics and some I don't. I have never prewashed precuts, have combined prewashed and not washed, but I do wash completed quilts with color catchers without problems. I can sure understand why you didn't feel up to prewashing and ironing, etc. So my advice would be to just finish your quilt and then wash and I think it will work for you. Quilting will keep it from shrinking unevenly.