Your mind is so powerful. I can go from zero to dead in about10 seconds. always been that way, but I am much better about it than I used to be.
What I do is to sit and say, ok, do I know that something is wrong with me,right now. not tomorrow, not 2 days from now. this second, this minute.
I am breathing, I am ok. Take deep breaths, meditate, pray, or whatever you want. Distract yourself. Clean, make a snack, watch something stupid on TV (reality shows have a way of making me feel better about my life lol)
Most people with HA have absolutely no legit symptoms, just ones their minds make up. You have to see if the symptoms go away when you are concentrating on something else, if they do, they aren't real.
Hope that helps