Furadantin and antibiotic

My daughter is 3 and has had recurring UTI infections for over a year now. She currently has a UTI infection that is resisting the antibiotics. She has had this infection since December. The doctor prescribed Furadantin. This is the fourth antibiotic she has been on to try to stop this UTI infection. Anyways, the Furdantin is making her sick. She doesn't want to eat, her stomach hurts, she is extremely tired, and she is vomiting. I always make sure that she eats before I give it to her, but sure enough about 10 minutes later she is vomiting all over the place. I hope there is another medicine that can help my baby, without making her so sick. I feel awful.