Thanks, everyone. I'm pretty sure this is related to surgery. With 4 surgeries in 16 months, I really haven't had time to recover from any of them. Even though the 3rd surgery was minimally invasive, I had a really hard time recovering from it. I was just starting to feel more "normal", though still in constant pain, when I learned I needed the fusion.
Cary, I agree that most people, doctors included, underestimate what surgery and being under general anesthesia can do to a person. I really thought that most of my symptoms, particularly the concentration problems, were just a side effect of the pain killers I was on. However, I've cut the pain killers down to about 25% of what I was taking previously, and it hasn't helped. I know my father had some of the same symptoms following heart surgery, particularly the hand/eye coordination issue. He was always dropping things, which was very uncharacteristic.
I'm going to try to see the psychologist for advice, and just hang in there until I recover more fully. At only 4 weeks post-surgery, I'm still limited in what I can do physically, and it will still be a few weeks before I return to work. Thanks again, everyone.