Shots actually temporarily weaken a cats immune systemThe cat you saw had either Herpes or conjuctivitis but your cat could not catch it from you. .There is a world of airbourne bacteria in animal centers even if you do not see sick cats.
It is normal for your babies to feel a bit under the weather after vaccnations but they should not be hiding or not eating.
I would have the sick one checked out ASAP. He is going to get dehydrated if he does not eat.
In the meantime,give h im two droppers (cc size) of unflavored pedialyte every ten minutes for an hour. Next water down(plain water) canned cat food or baby food chicken or turkey with no onion or garlic and give only one dropper every ten minutes for another hour. Wait two hours and repeat both. When he feels hydrated he will lick up the gruel on his own.
Boil chicken or fish as the scent of food cooking awakens the appetite sensor in the brain.
Please get started ASAP and let me know how things are going. I will stand by to hear from you and help further.
Cats do not have whims like people. Whenever they stop eating n or strart hiding, are either ill or in pain. If he has no other symptoms like fever, diarrhea, constipation, infection, etc then there is something going on that is difficult to ascertain - but it exists nevertheless. They can be mildly dehydrated or have a metabolic or organic imbalance that is too slight to read on a test. He may also feel nauseated.
Vaccine reactions can be serious:
I would get him out and offer someting tasty like people tuna, baby foood or boiled chicken.
Make sure he has no fever above 102.5.
If he refuses to eat or has fever or is dehydrated, he should be reseen. I do not agree with the philosophy of "watching" a sick cat because he can get worse from not eating or dehydration.
Hopefully he is just stressed and upset but do try to get him to eat.
Please let me know how he is feeling. I will be standing by to hear from you.
I am sooooo glad your baby is feelig better! Yes, many cats have reactions to vaccines.
If your vet used climydia vaccine in the FVRCP, that may be the culprit as it often causes eye issues so I would leave it out next time
Indoor kitties do not need FELV shots.
I will be here so please let me know how your baby is doing.