Advice for Overcoming Interview Anxiety?

Hello!

I’m hoping for some advice specific to interviewing at public libraries. I’m in a large metro area and applying for entry-level (page/aide/clerk) jobs that are mostly through city governments, ranging from single-building libraries to systems with dozens of branches. I have some paid library experience, a lot of volunteer library experience, and good references from well-known libraries and programs. However, I have absolutely, painfully failed the two interviews I’ve managed to get. I don’t understand this because I’ve had pretty good success interviewing in my previous career and even for a student library job I held, and I've been assured by the Librarians I know that I 'have what it takes'. Something about these public library interviews makes me panic and malfunction despite thorough preparation, researching interview questions, preparing anecdotes, and practicing my answers to all kinds of hypotheticals. I rambled, my hands shook, I used obnoxious filler words that I rarely use in normal conversation, and accidentally ended it with five minutes still left that I could have used. At one point I even interrupted the interviewer and then audibly gasped at myself for the mistake. I smiled through all of this but I'm pretty sure I looked like Mia Goth during the end credits of Pearl.

Does anyone have practical advice? Is this universal? Can I ever get a library job if I can’t overcome this lapse of sanity every time I face a panel? I’ve thought about asking mentors to do practice interview questions but I don’t think I can simulate the pressure that accompanies the real deal.

Thanks in advance!