I'm not sure you did anything wrong middy. I always make mine with a 1" seam too. If you made a fairly large one, and especially out of denim, it's bound to be quite heavy by the time you get almost all the rows on. It sounds to me like you did it the right way. I've never used denim, but even the ones I've made from flannel with just a thin batting got heavy to work with. All I can do is support you and be your cheerleader!! You're almost done from the sounds of it. ONward girl! You can do it. :)