All info lost suddenly in Ical, no sync with gmail

My calendar went suddenly blank (removed all previous input)

- OSX 10.9

- Calender 7.0 (1835)

Sync. with calendar in Google Gmail (this is working perfect), ipad (calender seems to be ok here)

I think it is a big problem when my calender is suddenly wiped out without me doing anything,

Should I drop apple mail and calender or ??

Ihave checked for sync. with Icloud..any good idea or fix?