My account has just. . . . disappeared!

I opened my imdb app this afternoon and everything is gone. Years of curated lists have disappeared. My account got logged out somehow and when I attempt to log in again, it does not give me the option to sign in with my email address and password anymore. So I select sign in with Google/Gmail because my account is a Gmail account. But it tells me that there is no account found. It's just gone! What is going on?!?