Kitten day after spay

My 6month old kitten was spayed yesterday and was fine until tonight. She cries and hisses when I pick her up (carried her upstairs to her bed) and doesn't want me to look at her stitches. She's wearing a Suitical so that she and the dogs won't be able to get to her stitches. She's been in her bed the whole evening, and she's very uncomfortable, she didn't want to eat tonight and haven't been to the toilet in 5hours. There's a bit of swelling/bulging around her stitches. I know it's major surgery, am I just too much of a helicopter parent? Will she be fine until my normal vet opens tomorrow morning?

Edit: Took her to the vet. They took an xray and everything is fine, just a seroma. Dr thinks it's a reaction to the middle layer of sutures. She got something for pain for the next 4 days. Thanks for all the help!