It sounds like you are retaining some fluid which is going to happen because you've been unable to pee, even with the bag. Do you still have the catheter in?
If so this might need to be checked to make sure it is draining properly.
One of the times I was catheterized it kinked inside causing me to swell and gain loads of weight. They had to remove it and put another one in.
It's going to take some time for the fluid to get out of your system.
Did you tell the doctor about the swelling of your feet?
He might want to put you on a directic.