My calendar is gone! What happened and what can I do?

My calendar is gone! What happened and what can I do? - Users - Troubleshooting | Google Groups:

"Howdy everyone,

So, glancing at the Help Group threads, I often see a lot of reports
saying, “my calendar has vanished” or something similarly alarming and
understandably distressing. I’m hoping that I can throw out a few
scenarios to help confront these issues proactively and reduce the
amount of time you’re all waiting for an answer or assistance.

There are generally 4 different situations to explain the “my-calendar-
is-gone” woes:

1. The calendar in question still appears in your list of calendars
but is unchecked. Checking this box should display your events. If
checking the box has no effect and it’s your primary calendar (the one
at the top of the list) – go to #3 below.

2. If the events on your primary calendar aren’t displayed (even when
calendar box is checked), it’s possible that you or someone sharing
the calendar accidentally cleared the calendar. A primary calendar is
cleared of events by selecting the trashcan icon next to this calendar
in the Settings menu > Calendars tab. We can’t restore events on a
deleted primary calendar :(

3. You have multiple Google Accounts and you’re logged in to the wrong
one. Sign in with alternate email addresses to see if your events and
calendars appear.

4. An entire secondary calendar is missing from your list of calendars
in the Settings menu.

- Please contact us via email to resolve this issue further. While we
encourage posting in the Help Group when possible, some matters
require sharing email addresses and personal calendar names. To
contact us regarding deleted secondary calendars, go to
http://www.google.com/support/calendar/bin/request.py and select 
"Get
help with a technical issue." Next, choose "Access & Loading 
Issues"
and read through the info to reach a contact form.

In your email, you should include:
o The email address used to sign in to Google Calendar
o The name or names of any deleted secondary calendars
o A link to this thread

Thanks for reading,
Becky