Difficult Baby

Has anyone had an extremely difficult baby?

I've had prior kids before and life was hard, I had a baby, babies are challenging. But THIS. This baby is on an absolute different level. I love my baby to death, I will go to the ends of the earth for them and raise them as best and loving as my others, but I'm at a loss. Almost 5 months in and I have come to realize how different and hard of a human being they are going to be. Does this change? If you had a difficult baby, did they get better as a toddler? A child?

I'm just so at a loss at this point. They meet every moment with fight and chaos. I've had them evaluated for everything in the book. Healthy and strong. On charts for percentiles. But just a fighter!! At every single turn!! I'm so tired. I keep waiting for them to round the corner, but here I stand, everyday. It affecting my bond and I find myself unhappy.