I'm going to say something here which should/probably will be deleted - I am exactly the same, I suffer from CPTSD and GAD.
Massive social anxiety to the point that I'll cancel something I really want to go to because I'm so scared of having a panic attack and being "humiliated" in front of my peers, and the knock-on affect on my self-esteem having "failed".
I put that in "quotes" because of course it isn't failing or humiliation - it is just my fear of it.
I would recommend therapy to discuss why you feel so unusually anxious in those moments. I did it myself and it really helped. However, and now we come to the deleting part of my post!
Therapy takes a long time and hard work if you can even afford to go private, and if you are waiting on NHS then fucking forget it!
Go online and buy Alprazolam 1mg tablets. Xanax. Take half (0.5mg) about an hour before any interview and you will feel focused, calm and "real".
Please note - Benzodiazepines taken for more than about 2 weeks are highly addictive. DON'T GO THERE!! World of horror.
Once in a while for moments of pure panic/anxiety they've saved my life.
If you have a history of addiction on booze, dope, gambling, knitting, etc, please don't go there. However, some things are more important if you haven't, I couldn't have got my job without them, to get me over the interview, first week stage.
Be well.