My daughter is 9 years old and was prescribed Omnicef for a sinus infection. 48 hours after first taking her dosage, she was in a deep depression. It was as if her "light" went out. She cried, worried and obsessed about things that she didn't even understand. Many times she said that she had no idea why she was sad and crying. I took her to the school psychologist who couldn't put her finger on any certain concern either. This went on for 2 weeks. Exactly 48 hours after stopping the drug, the light came back on. She has been fine ever since. Has anyone else ever had this happen to them?