Spayed kitty

So i have had my cat for a year now along with her sister. they both had kittens a week apart 5 months ago, i kept one from each litter... & on tuesday i took all 4 of my cats to get fixed. My cat Shuggy was a complete sweetheart but ever since she got fixed she hisses at the other cats & hides in the bathroom cubbard. my fiancé said it is probably because she’s in pain, but none of the other cats are acting that way. i am actually worried & my fiancé says he feels they were mean to her. i’m not sure what to do i just want my sweetheart back so we can all be cuddly again ☹️