Welcome. I am sorry to read about the decision to declaw the cat. However, that is water under the bridge. You mentioned that your cat has an infection? How do you know this? Some cats will limp or favor a paw for months after a declaw. To help ease your mind some, this might not mean anything is necessarily wrong.

You can try confining the cat to a room with nothing to climb on, to discourage the cat from jumping down, and hurting his/her paws. If you suspect it is an infection, please go to an animal ER. Monday is too long to wait.

What sort of litter are you using? Did you use paper litter for 2 weeks? Could the cat have something stuck in the paw?