These are techniques I have picked up over the years to help me fight this anxiety or make me feel better when feeling really bad.
When having a bad anxiety attack/panic attack you need to distract yourself. I try everything from using my laptop to playing games. If you feel a little better then start to do some breathing techniques such as breath in 8 seconds through your nose and out 16 seconds through your mouth. This will decrease your heart rate. The thoughts you need to be saying are: I can only be in a hightened state of panic for a short amount of time so it will go away, it can not harm me and I will not die or go crazy ( big one for me as I always think I will flip out).
One of the things you need to set your mind to,