I'm so sorry you're feeling this way, anxiety is a horrible thing, it can effect us in many many ways. Have you tried counselling/therapy? Sorry if you have already mentioned this, I may have missed it. I'm doing therapy at the moment and it really is helping, just having someone to talk to who can help you understand your feelings really helps. The symptoms you are describing are classic panic attack symptoms, the more you worry about them, the worse the panic gets, its a vicious cycle and very hard to break. Im sorry I can't be kuch help, im going through similar myself and struggling to get out of it. The things that help me when im having negative thoughts and i start panicking are, deep breathing exercises and meditation. I downloaded a relaxation app on my phone that really helps also. I also try to imagine myself putting my worries and negative thoughts into boxes and locking them, and then replacing them with positive thoughts about things I enjoy, this also helps sometimes too.
Again, im sorry I cant offer more advice but I hope someone else can, remember youre not alone and you can get through this!