A phone call to the vet won't hurt.

Each cat reacts differently. I have Crystal, who is her bouncing self an hour after all her shots. Sparkle takes a day or two to get adjusted. Vita just sleeps until she feels better - or hungry enough to move. Chestnut, well, nothing noticeable with him. I guess he must lay low for a time and then get into his normal routines. Ruffles sulks at the indignity of it all for a couple of hours, not sure that the shots themselves bother her!

My vet has notes on file for each animal. I get a follow up phone call for Sparkle and for Vita 2 days after the shots are given, to see that they are OK. I think this got set up when they were young and I phoned in the first time I had them in there for their shots. (Different cts, different years, go in different months for their shots.)

Hope this helps.