Due to my impatience, I called CIS to ask about my case. I dialed 1,2,3 and 4 and used the whole "it's been 30 days and I haven't yet got a receipt for my I131" and it worked PERFECTLY, so thank you for that tip, forum people. I was told that I am in the queue for an interview, so I guess that means my background check was done? The IO also said that the NBC sets the appointment date and THEN transfers the case to the DO, while I was under the impression that they transferred the case first, after which the DO sets a date, so I don't know what's true. Anyway, it's good to know something new, without which my head would probably explode. I need to take up meditation or yoga or something...