Omnicef and aggression

Started my 2.5 year old son on Omiceff 6 days ago for ear infection. Has been having very weird bowel movements, dark and clumpy and liquidy at the same time. Worst is his behavior extreme changes in personality, showing aggression and anxiety. Hitting, tantrums x10 ( not the typical terrible 2's kind) crying, irratable, and will not nap. Finally today all of a sudden he began screaming in pain saying his groin area hurt. He would not let me look let alone touch. After 30 minutes of inconsolable crying, I put balmex and he calmed down I hope it is nothing worse than a diaper rash. Called the DR advised me to finish the 10 days, did not respond to behavior concerns. Want to hear my prognosis: STOP TAKING OMNICEF. I will not continue to put my son and our family through this horrible ordeal. If his ear infection returns they can put him on Augmentin. Enough is Enough. Sometimes we have to listen to our own intuition Dr's only go my want the Pharm Co. has to say.
Concerned Mom