It could be very possible that your dog is stressed out. Dogs are by nature social animals, not loners, and you are her society. She may still love you but feel abandoned. A dog sitter coming in might work for a day or two with some dogs, but a month is a long, long time.
Expect to replace your carpet and the pad, and to do major cleaning to whatever is under the pad, in order to get the odor out. Professional companies know how to do this. You'll have to talk with your insurance company about whether they cover the expense.
When you get home, give your dog lots and lots of love. If she doesn't want you out of her sight, you can't blame her. Give her lots of attention, take her for walks, play with her, and begin to establish your relationship with her again. Just as if she were a puppy, take her outside after every meal, every nap, and every period longer than a couple of hours, just to get her back on the right track. Keep clean-up stuff handy for mistakes while she gets used to the regular routine again.
It would also be a very good idea to have your vet check her out just to be sure there isn't any infection or other reason that she would "do her duty" inside rather than waiting to go outside.