There are people here who can tell you how to use the calendar properly and sync with whatever you want (where it's possible). I can give you my opinion and tell you what I do, which will work, but doesn't involve google or facebook. If you want to use google sync, though, there will be others to give you the info you need to avoid problems.
At any rate, the data that has been lost on both the BlackBerry and Outlook is probably gone. If you have a backup from before you lost data, you could do a selective restore, but that will overwrite any new entries you made since the backup. It may be easier to fix the calendar in Outlook and re-enter appointments there, and then re-sync to the BlackBerry.
So, the next question is what do you want to do? I can help you deal with the multiple calendars and sync with Outlook. I can't help with google sync.
In the meantime for background, see KB17992-Using the Calendar application on a BlackBerry smartphone that supports multiple CICAL service books
. Posted via BlackBerryForums.com Mobile