4 month old kitten vomited a big amount-- food or reaction to deworming?

She was at the vet 3 days ago and got  the final round of her FVRCP vaccines, as well as a deworming and Revolution for flea and heartworm. She has been completely fine up until now and didn't show any sign of a reaction, so I think it's probably the food? 

I like to give her a new type of wet food every few days. The vet and my research said it should be fine to rotate types of wet food quickly as long as she has had the ingredients before, and up until now it hasn't been a problem. 

This morning I opened a fresh can of food, a type that she has had before a few times with no problems, and she ate it right up. Then, within an hour, she vomited all of it back up, then had a tiny bit of diarrhea in her litter box. That was about 15 minutes ago and since then she seems fine. She drank a little water and ran off to go play with her feather toy. She isn't acting sick in any other way. 

I'm probably going to throw this food away and give her something else. Should I wait to feed her again, or feed her something different? Or is this more likely to be a reaction to what they did at the vet and I should take her back in? 

I'm wondering if I should try to feed her again soon or if I should wait 12 hours. Some websites are saying that when your cat is sick, don't feed them for a long time. I don't think she is ill, and she only vomited once. Should I still wait?

It's been a long time since I had kittens, but I probably wouldn't wait that long if she acts hungry?  I might not feed her as much as usual, but I'd just kind of play it by ear.  See how she does. 

BTW, I doubt it's the medication since it's been so long.  May have been a bad can or bad batch of food.  One of mine threw up this morning too and I never figured out why.  But he wanted to eat immediately afterwards, so I fed him again and he was fine.  He's 7 though

Yeah, I waited until she showed some interest in her kibble (which is always available but she rarely chooses to eat) and then gave her half a meal (from a different can), then the other half an hour later. She seems fine so it was probably just a weird batch of food. I threw the can away.