Cat vet sleepy post booster injection

[Orangelover]

Took my little boy cat to the vets today for his booster jabs, he had the full once over from the vet (given clean bill of health) and his injection and was generally quite well behaved!

When we got home he was was a bit sulky but ok. Still played with his toys and went in the garden for a bit. But since tea time he's really drowsy and sleepy, very unusual for this time of day. He's just been asleep on our bed all evening when usually he likes to be with us on laps or popping in and out the living room. He's just not himself

Should I be worried? I'm panicking that he's having a bad reaction to it or something. Or I've traumatised him by taking him to the vets for the first time

I think they can be a bit off for a day or so afterwards. I think one of mine did the same once.

It can make them tired as their immune system makes the antibodies, you can ring the vet if he seems poorly.

Well after an evening of him being all floppy and me panicking he popped back up this morning right as rain Seems fine today and has scoffed all his meals and is back playing with his toys

Thanks guys!