Help! All my past calendar entries are disappearing after 1 month

Hello,

My old calendar entries get deleted automatically after about a month has passed. I have been living with this for at least 4 months now. I have stopped syncing with Outlook, and my blackberry or via itunes - hence calendar is not totally standalone - but the issue still persists.

As you can tell, it is driving me a little crazy :-P

I saw online people saying to check my setting for "Mail,Contacts, Calendars -> Calendars -> Sync" but I do not have this field ( Only "New Invitation Alerts", "time Zone Support", and "Default Alert Times").

Your help is *greatly* appreciated!