Thank you rewt, your kind words make me feel better right now. =)

Today I had an terrible phd interview, it was my first interview and I thought I could ace it but it turned out to be a mess. During the preparation phase, I even wrote down 10 questions that I might be asked; I was expecting the interviewers to ask me something related to my future research or my motivation for being there. Sadly, they didn't ask me that; however, my questions, for the most part, were about my master thesis, and I thought that I was having another master oral defence. It was a real surprise that they even asked me how my master thesis project can be applied to artificial intelligence, but my major is cognitive linguistics not computational linguistics, and seriously I didn know how to answer it.
This bad interview experience has already spoiled my mood to prepare for the next phd interview, I know I should brush it off, but the image of that interview moment keeps popping into my head, what should I do now?