Strept throat symptoms and conditions

I am a seventeen-year-old and I have been prescribed Omnicef twice for strept throat. The first time, a few months ago, I noticed that I became more aggressive and agitated a lot easier (here I might add that I am normally an oddly happy teenager). This is my fifth day on Omnicef and I am suffering from severe depression, for no apparent reason. I've heard of others experiencing the same, and my aggressiveness that disappeared at the same time as my medication the last time around is back again. I wonder if this is connected to the crankiness described by the parents of the toddlers?

I am on 500mg for strept. throat. Since being on Cephalexin, I have had almost migraine like headaches including nausea. Bright light is very irritating and a few times I have felt as though I might pass out.

Rob