I'm so sorry that you're going through this. I know that there's probably nothing I can say that will help but I'll try. I had a lot of the same fears with my 4th about not being able to bond, but as soon as he was born I fell in love. He is the child I was always waiting for and he completes our family so much. All of the kids adore him and he loves his big brothers like nothing else. He is such a special little soul. I know it seems like you're just doing the same thing all over again but your baby is his own unique person and it's going to all be brand new and wonderful, I promise.
Even though it's hard, try and prepare for him to join your family. As someone here once said "fake it until you make it." Give him a name, set up his crib, and pick out just a few new things for him. It helps a lot.