I did call today. When i turned in my transcripts I asked about the interviews and the girl in the front said they usually recommend a phone interview before an in person. I had to sign up and schedule a phone interview which was a very basic casual conversation really about my grades and whatnot. It didn't seem required. The interview was a few days after I handed everything in, but again i had to volunteer myself for it. I don't think they'd pursue it otherwise so if you didn't do one I don't think it will make or break you.
and I totally understand the nerves! Everyday at 3 I'd check the mail and for the rest of the night would have my stomach tied up in knots. I'd recommend calling and if at least to know your application is complete and is being reviewed. I'm grateful I did as there was a slight mixup with my app. They were extremely nice about it though. good luck!