Vaccine reaction or just stressed??

Hi all, my 6 year old cat, spayed female, went to the vet today and got the rabies, FVCRP, and feline leukemia vaccine. It’s now 11 pm and so about 9 hours since she got them. As soon as we got home she threw up a few times in a row then went under my bed and just meowed and came out occasionally to try to use the litter box but that’s it. I went to take a shower and came out and she used the box but it was very loose stool with bloody mucus. I called my vet she said to monitor until tomorrow afternoon but that’s it sounds like stress induced colitis (she hates the car and did not tolerate the vet visit well). Fast forward to now, she came out from under my bed and threw up one single time then stood by her food and water for a while before deciding to lay down in her fav place (the cat floor hammock lol) and seems better but just kinda confused and tired. I know she hasn’t eaten but she could have had water while I was in the shower so unsure on that. Has anyone else experienced this level of a stress response in their cats?