Michelle, I am so sorry I missed this earlier. I am sure that she will be fine. Both Rusty & Fluffy both had terrible reaction to vaccinations last year. Wouldn't eat, lethargic, growling, no litter box use. I was scared. Called the vet and they said most likely a reaction. Has caused me to think twice about vaccinations. Anyway that is another story. Give her another 24 hours and I am sure she will be her old self again. I am sorry you and she had to go through this. Yes, each cat is different, so Vixen it may not bother at all.

((((Hugs))))
Hope she continues to improve quickly.