Does nervousness affect interview?
People who report more anxiety during the interview do receive lower interview scores (as judged by interviewers). The effect is not huge, however.
Should you apologize for being nervous in an interview?
Think twice about that interview thank you apology!
In general, it's best NOT to introduce anything new (like being nervous in your interview) that might undo all the hard work you put into that job interview.
How do I deal with severe anxiety in an interview?
Before an interview, figure out if you need to calm down or amp yourself up. During the interview, try and take deep breaths — and don't feel like you have to immediately start talking after a question. If you're still feeling anxious post-interview, try using some mindfulness exercises.