Just remember this is only one job of many. If you don’t get it you can apply elsewhere and find a better job. Be confident that you are a competent organised human being. You can pick up the phone, you can log appointments and juggle multiple tasks. There is nothing preventing you from doing great in this role. Also the interviewers are human beings and normal people just like you are. There is no logical reason to be nervous (not that this fact will help) but it is worth trying to keep in mind. You are probably already doing it. I would strongly recommend applying for lots of jobs. It means interviews matter less as you have another 10 applications in progress. It is less of a big deal what happens on the day. It takes some of the pressure off.