I've posted in chat too, now I can't sleep as I'm so worried, so have wandered in here for nice cat stories!
My beautiful 10 week old kitten had her first vaccinations today - popped her in the bedroom after so she could be nice and quiet away from the other cats, checked in on her every so often and she seemed fine, a bit dopier than usual bit that's happened to the others after their injections.
Popped in for a cuddle at about 8pm and found her all floppy and weak, not herself at all. Phoned the on-call vet who said to bring her straight in.
The vet was really worried too, and said she'd never seen a kitten react so badly after vaccinations. The poor thing was still floppy and shivering by this point, and had a very high temperature, so had to leave her behind.
Rang the vet as soon as I got home - kitten had put up a bit of a fight to having the IV line in which is promising, and she's having antibiotics too. The vet promised to call if anything changed and I haven't heard anything so I'm tentatively hoping that's good news!
Photo is from earlier when she went for her jabs.