Okay I understand totally what you are going through, and being someone who has suffered Anxiety and panic attacks for almost twenty years I know what I am talking about:
What you have described is something I experienced as well. The brain is an extremely powerful thing and has an amazing power of suggestion, and control of feelings and thoughts. The key thing you have explained and highlighted is control, you are thinking of a situation that is completely beyond your control, that being your existence. If you feel panicky, say in a shop, you can leave the shop, if you get panicky in a car, you can leave the car, and so on, but now what you are doing is thinking of a situation you cannot escape from, and that for an anxiety sufferer is scary, because control is the main factor of anxiety. One thing I remember about my anxiety was the strange feeling about who I was, and that I can never run away from myself and I was stuck with myself. You talk of buzzing sensations, I used to feel like I was hooked up to the mains sometimes, I had huge jolts of energy just pulsate through me and many buzzing sensations. This is usually nerve related. One thing I have learned over the years is to let go of control, because it consumes your life and rules your life too. Another thing I do is I try to keep my brain active, that is very important I do anything, read boring books, do crosswords, puzzles clean, write books (Never published just to occupy my mind) if you leave your brain inactive it will go into itself especially if you suffer from anxiety. A panic attack is a truly frightening experience that unless you have suffered one, will never understand. The fact is the modern world is to blame the stress, and fast moving lives we are not built for, the media, films, video games, the internet, and so on. I have found that taking myself out of this helps me, I do not get bogged own in modern life anymore, I don't watch the TV much because that can influence my mood allot, the same with the internet and all its bad news, I quit smoking and drinking, also reduced my caffeine intake all these help to feel less panicky. It is hard to tell another it will be okay, because when suffering anxiety it seems hopeless, and that this is your lot forever, but it's not so, you can reprogram your brain, it takes time and many ups and downs, but you can do it, remember it's your brain.