CHERRYY Cuttita

Had 2 emails today asking if I have changed my account. I HAVE NOT. Another email said my email address had to been changed, I HAVE NOT changed any of my details at all. I logged in and my Lindens have all gone. My inventory is gone too. A new avatar on logging in, what on earth has happened. I need to know what to do URGENT PLEASE HELP as i am afraid of them hacking my bank details. Everyone is scared and they are thinking of closing their accounts in SL . PLEASE HELP