iphoto put all pics in 1 "Event", iphoto put all pics in 1 "Event"

I updated to Mountain Lion aprox a week ago, I hadn't gone into iPhoto until today when I hooked up my iPhone to download some photos, I did so and then found out all of my 5,700 pics that had been separated into multiple Events were now all in 1 single Event. I checked and there are no system updates. I also did a "rebuild database" but that didn't do anything. I also, of course did a complete shut down and restart of my system (twice). Please help!