My cat pooed in the shower!
My cat wouldn't go outside for the day, so I let her stay inside. When I got back at the end of the day, she had pooped in the shower tray and she somehow flicked the shower tray up with the cat poo on, and it went everywhere!
That sounds like a mess! I'm sorry to hear that your cat is having problems. Without more to go on, I'd speculate that because your cat's usual routine was disrupted, she used the shower instead of the litter box.
Digging deeper, I would ask why your cat didn't go outside, whether or not that's unusual, and if there are any other signs of either behavioral changes or illness.
I'd also be curious to know whether or not the litter box was in perfect operating condition that day. If it wasn't up to your cat's standards, that may have contributed to the problem.
As always, you should report any behavioral changes to your vet, and get her a check up to make sure she is healthy.
I hope that helps.