What Causes Lack Of Appetite And Diarrhea While On Cefdinir?

3 yr old grand daughter w/ first febrile seizure. Temp of 103. Taken to ER. Diagnosed w/ bladder infection. Given Cefdinir oral suspension 5 M b.i.d. This is day 3 of medicine. Last night ...all night...restless, twitching, awake on/off. ( no appetite, diarrhea, ) Is this a normal side effect? She s never had any type of antibiotic before. Or fever .