What can make a cat go crazy?
As some of the other answers have indicated, your cat has a lot going on right now and needs some time to settle back down. It probably wasn’t the best idea to bring in a new cat around the same time one was having kittens, but since nothing can be done about it, you just need to give mamma cat more time to adjust to everything that has changed. Cats are temperamental creatures, which I’m sure you’ve noticed if you’ve had them around awhile. If she’s still acting this way in a couple of weeks, it’s probably time for a vet visit. Even if it’s still only stress, they’ll be able to give you solutions (and maybe even medicine) to calm her down. They deal in behavorial changes just like physical ones.
We had many cats at one stage a few years and ‘my’ cat had kittens. She was very protective of them, and started fighting with the other cats too, it’s best to make sure that other cats can’t get near the new mum and her kittens. When the kittens got taken away (and we had two females one had 2 litters one had 3 this what happens when you don’t neuter your cat) the mum would pine for a week or so, and it took a while after that for her to be friendly to the other cats again. Cats in general especially unfixed ones get very odd when there are new things in the house. My grandmothers cat went A-wall when she got a new shelf unit and sprayed over it for weeks and would growl at it when he walked passed.
She will be normal again with time. Lots going on for her right now. She is I am sure mad at you for introducing another cat. She is acting out to let you know that she is mad at you. I think that is what is going on. If she was upset about the kittens being gone she would be more lazy and depressed. The fact that she is acting out shows she is trying to get your attention. She probably feels jealous of the new arrival. Give her lots of love. She will go back to normal with time. Everything just needs to calm down first.
You’re a woman with regular period and should understand the idea of ‘those days’. The cat is just having ‘those months’. Just had kids, body is changing, you introduce new cats at the same time, of course it’s flipping out. Just give it some time. And make sure to protect the kittens, sometimes new cat moms can even kill their own babies, depends on the cat.
