Well, I had wildly fluctuating emotions before surgery that were all about being nervous about the surgery, ranging from excited to terrified. I was so nervous on the day of the surgery that I almost called it off just before I was being wheeled into the operating room.
I'm guessing that your emotions do have a lot to do with your upcoming surgery, even if you say you are not nervous. You should also be aware that there will be lots of ups and downs after surgery as well. That's where this forum can be really useful, because you'll learn that what you are going through is not unique.