My Almost 6 Year Old Cat Has Been Lethargic Ad

my almost 6 year old cat has been lethargic ad not eating well at all, she has bad breath. I am taking her to a vet tomorrow, but because her rabies shot is long overdue, they said they will have to give her one when she comes in for an exam. Question: If she needs a shot of antibiotic or is sick, is a rabies shot in order at the same time?