Was busy with editing my appointments in the Calendar, which is my trusted daily task scheduler. After moving an appointment to a different date, I locked the phone and proceed to do some office work. When I unlocked the phone, suddenly the calendar shows only the public holidays, all data which is Important now Gone

I even restarted, Data is missing still
I unSync and reSync, Data is still missing
I uninstall Google Calendar app, and reInstall, Data is still missing

Important Data is now missing, Please, Please Help me