Outlook Corrupted? Massive, Random Issues

Things just keep getting worse and worse with my Outlook in Office for Mac 2011.  I have spent hours on the phone with Microsoft, and have re-built my identity countless times.  This has been done to address a host of issues but each time we fix one thing, something else goes wrong.  The current issues are: (1) All of my sent e-mails appear in duplicate in the Sent folder and have to be manually downloaded by opening them individually; (2) Search does not work in mail AT ALL; and (3) when I accept a meeting request, it does not go into my calendar, the request simply gets deleted.  I'm wondering if my Outlook is just hopelessly corrupted at this point.  I should perhaps mention that I use Outlook with a gmail account.