My mother had her kidney removed in January of this year. It took a good 4 or 5 months before she really felt better. She got tired alot and had some pains, but it all takes time. In fact, just a couple weeks ago she told me she had the first day that she really felt "normal" since her surgery.
As far as going in for the CT scans, yes...you will need to go on a regular basis for check ups because this cancer can spread to other areas quite easily, and even after the kidney has been removed.
Early detection is the key, and I'd listen to your doctors. Don't delay the re-checks, and try not to fret too terribly much. I'm sure you had the CT and bone scans prior to your surgery, and if they looked good then, chances are you'll be cancer free.
I hope you feel better soon. Try to relax and take it easy...don't push. Your body went through alot, and it takes a while to heal.
Best of luck to you!!!