I am a supervisor in a distribution center. I also suffer from extreme anxiety which makes my speech worse, and I also experience physical pain from it, to the point of mental black outs. It is devastating to be intellectually capable of so much but not be able to show it and live up to that potential. I sit in meetings and just keep my mouth shut out of fear of getting blocked up but inside I have so much I want to add to a discussion. You will never escape in person interviews. I always practiced quick talking points before hand, it seemed to help. The anxiety I would experience before interviews is what made things worse, so I would just try to stay calm and confident. Just having to walk up to a desk and introduce myself and tell them I was there for an interview was terrifying, so getting past that and the rest was a breeze, your mental state starts to calm. I know the shit is scary man. I wish I had some better advice or more to add. Just don't give up.