My five year old was in the hospital for 4 days for a sinus infec...

My five year old was in the hospital for 4 days for a sinus infection and they put her on Omnicef. My daughter is a very cheerful little girl and these last couple of days she has been everything but cheerful. Its as she has turned into a demon over night. She has been having the worst mood swings. She has been screaming, yelling back, and kicking her legs and just being really mean. I remember the nurse advising me the possibility of a change in mood swings but I never imagined this. Omnicef did it's purpose BUT I hope to never have to use it again. I was not prepared for the mood swings my child acted out. I thought it was just my child until I started reading online and asking around.