You probably won't belive me, but I'd bet a beer that you've got some device that's connecting to your server, logging in as you, and downloading your messages.
Zimbra won't "wipe" an account.
A good way to check this out would be to check the audit log for people/devices logging in as you. Then go to the /var/log/zimbra.log for the coorisponding time, and look at the info.
I may be wrong, but I'm willing to bet on it. . .and I don't do that often.
Good luck.