I think for a good amount of situations, people tend to negatively reflect their performance (exams, interviews, etc), without even acknowledging the amount of hard work, drive, and passion they applied for that specific scenario (and not even thinking of the positives).....I do this too!
From what it sounds like, you will be fine! Everyone is a bit nervous, especially with interviews. I'm sure you said a lot of reflective and honest responses that interviewers liked to hear; a little bit of nervousness won't kill your chances!
Just relax, continue to do well on the other interviews, and you'll be surprised that when Dec 1 comes, that so called "non-optimal interview) will be a school that accepts you 🙂
Keep up the good work, and best of luck with the rest of the cycle!