Events missing from icloud calendars

I just discovered that ALL events for every single icloud calendar are missing from all my devises from prior to August 15th. What happened? Is there a way to restore without losing my current events? I am using iCal 6.0 on my mac and an iphone. All my calendars were also shared with family members and all events are gone. Calendars are still showing but my icloud calendar online also shows nothing prior to August 15th.