what happened to my lovable cat?

Can some cats have such a personality change as the age?

up until she turned 2 my cat was so affectionate to anyone and everyone, complete strangers could pick her up and hug her she'd seek out children because they played with her, then all of a sudden I am now the only one she tolerates, she does not hide the fact that she dislikes everyone else in the world, she growls, hisses, chases and swats at everyone now. in most flight or fight situations she is a fighter.

the vet did not believe it was the same cat when I brought her in for a check up, he had to sedate her to even get near her the doctor even warned me that I might want to think about not letting her in the same room with me whilst I sleep, like she would attack me.

I have had friends tell me to put her down and get a new cat, but she is like a kitten when no one else is around. she even brings her favorite chew toys to me for a game of fetch.