Cat bleg

I have a favor to ask of all of you, my readers. I'm hoping your collective wisdom can help me out. Our 7 year old cat started pooing on the carpet occasionally a little while back. She then abruptly stopped for a while. Then a couple of weeks back, when the weather warmed up, she started peeing on the carpet. The frequency of this has picked up, and now today she started pooing and peeing on the carpet. We have a vet appointment tomorrow to get her checked out, and we've started using a more cat pee specific cleaner on the spots. We've closed the windows in case an outdoor scent was getting her riled up. Beyond that, we're at a loss for this sudden bad behaviour on her part. Has anybody experienced this, and would you tell me a little about your experience. The lovely Mrs. Jib adores this cat, so I'd just as soon see it live a long, healthy life. Thanks.

Update
We've been to the vet and he has given us his prognosis: It's probably a bladder infection. We don't know with complete certainty because he was not able to take a urine sample because she did not have enough in her bladder at the time (they take the sample with a needle, by the way). The pooping on the floor is not uncommon with a bladder infection because the pain of peeing causes them to strain quite a bit and dropping a deuce is an unexpected side effect. She's been put on antibiotics and special food which will increase the acidity of her urine and dissolve any crystals that might be forming the more alkaline, infected urine. Hopefully she'll be back to normal in 3 to 5 days and free of the infection in 3 weeks.

I must say, I'm quite thankful for our vet. He is extremely knowledgeable and he takes the time to explain things. Our previous cat had a terrible vet and he was never able to explain to us why our previous cat died unexpectedly on his examination table. When we got our current cat 7 or so years ago, we switched to the current vet and he was able to tell us what our previous cat had died from just based off the description. It was a rare condition, which made it all the more impressive. He has been a great vet and great for the health of our pet.