I suspect you are too hard on yourself. Put it aside for awhile and then get it out and re-evaluate it. When you continue it, make sure you support the quilt somehow so it doesn't do the bunching up that you mentioned. I put an ironing board perpendicular to my sewing machine and it supports my quilt as I work on it. That makes a big difference.
Then wash it. That makes it look sort of krinkly and the quilting doesn't show so much.
If you still hate it, put it up again and pull it out in a few months. It will look better to you if you have had time to forget how much trouble it was to you.
I know exactly how you feel though, thinking that you ruined a quilt that you really like. I have done that, but I have ended up liking my final results. Hang in there. It doesn't have to be perfect to still be a good quilt.
Dina