Why not get a quilting friend to join you for a day to take a look at what you are doing and maybe it is something so minute that you missed. It is always hard to find your own problems. A fresh eye might be just the thing to get you back on track. You have a beautiful quilt started; however, if it is truly so frustrating and you can not solve the problems, might want to think about another design that you will enjoy. Sometimes, we learn a lot when working through a problem, but it is not a crime to abandon a project that causes us so much stress. Better to have a completed project that gives you pleasure to make.