Okay, Bayril is enrofloxacin an antibiotic, this should clear up and cystitis or any infection that she may have. The best advise i can give on what youve said is to try to encourage her with her favorite foods. Maybe try soaking some pellets or asking the vets for some Recovery food or paste, Burgess do a fibrevore recovery paste with is great for convolesing pigs, or theres recovery paste food by oxbow which is good stuff. Maybe having a go at syringing some food. Keep an eye on her poo's/wee's. Make sure shes drinking adequate and eating as much as possible. I'd suggest if shes not properly for a couple of days get her to a vet. Does she struggle to eat? She may have a dental/oral problem. Did the vet look in her mouth on examination?
*If you havent seen her wee AT ALL, please get her to a Vet asap. She may have a blocked bladder, this can be a serious condition, this may be the reason why shes so lethargic. Having a blocked bladder can mean that toxins circulate around the blood as they are not being got rid of by the kidneys and bladder*
Please get her to a vet if she hasnt wee'd
x.