curious about change in behavior
hi, i'm new on here. my mother recently got a cat from the local shelter. she is 3 years old and she had been in the shelter for almost a year. apparently she had been traumatized in her first home after her owner had died. no one was interested in adopting her from the shelter because she was so shy. we decided to get her because she seemed so sweet. the first week home, she did very well. after the first day she let us pet her and even pick her up to cuddle. we got her lots of toys and she has been very mischievous and excited about her new home.
but the past few days, she has started hissing and seems to always be in a bad mood. she won't let anyone touch her and she doesn't want to play as much. she is neutered and an indoor cat. what could be the cause of her sudden change in behavior? we just want to make sure she is happy in her new home.
also, is it possible for neutered cats to still get pms? not an actual period, but the behavior that is associated with one.