No one is comfortable during interviews, they feel uneasy and just cannot relax. You are not alone and there is absolutely nothing wrong with it.
I recommend working with your peers and practice your interview skills. There are countless number of common interview questions online, just keep asking each other.
I suggest asking random and unexpected questions then going with structured ones. That way -just like in real interviews- you will be prepared when the interviewer asks you a random question all of a sudden.
Don’t forget: Practice makes perfect!