Wow! You are really being hard on yourself on this one! I think its really pretty and while you know where your mistakes are, 90% of the population would just be impressed with the quilt as a whole and not even see them. I'd either finish it up and donate it now if you can't stand to keep it around, or put it away for awhile and move onto something fun and when in a better state of mind pull it out and take another look at it.