So sorry about that @ThreeBeanChilli . Try not to lose heart. Interviews can be very very hard especially when you're stressed about them beforehand.
I have been for many jobs that I haven't got, and I worked out afterwards that it wasn't always the interview that made the difference. Sometime the interviewers would have a candidate in mind, something it's impossible to prepare for, sometimes - at least on one occasion - at the top of my paygrade, I was too expensive. Sometimes I just messed up the interview. so I decided to prepare my interview technique.
I had been for a couple of unsuccessful interviews before I took the interview for my last job, and decided that wasn't going to be why I didn't get the job anymore. I practised in advance being 100% positive about my achievements and my work record. In the NHS they always ask you something about your weaknesses and I had found that difficult to answer in the past, didn't know I was autistic, wanted to be honest. So I decided that I would be determinedly positive about everything. Yes I do have weaknesses, they are X and Y, and the strength in being able to account for them is that I know what they are.
I had done research on the organisation I wanted to join and was able to answer questions competently and positively BUT one of the things I read in my interview preparation technique was that getting everything right in an interview is not essential, it is more to do with how you present, and talking too much is not a thing.
It was a big effort though. But I got the job. Then when I started the job I realised there were a lot of things they hadn't told me. But that was okay because I wanted to work there.
It was my last job because after that I retired.