i know exactly how you feel, and I'm dreading taking my fur baby to the vet to have it done in a few hours! mine had it done in the afternoon, and until the evening after she looked really poorly, and like yours she would "cry" if i tried to move her, didn't eat anything. Then all of a sudden, after lots of sleeping, she just got up and started playing again, and the morning after she was full of life as usual.
in the end that's the effect that a vaccination has on a human baby too, it does make them a bit poorly. At the time I read somewhere that if it lasts for more than 48hrs then you should refer to the vet, but any less than that is pretty normal.