My therapist told me to stop using Google every time I feel random aches and pains and to take a deep breath, write down what I'm feeling, and then think about the health issues I already have. Almost all of the time it's just a symptom from that. It puts my mind at ease because then I know how to deal with it. Like, I fear my appendix is going to randomly explode so every time I feel a pain even remotely in that area I freak out and start Googling. But then I remember that I have constipation issues and I usually feel it in that area. I'm still working on health anxiety myself so I hope this helps you!

Distractions when you feel it coming on instantly distract yourself with something around and sometimes look yourself in mirror and just say I'm ok nothing is wrong can help to but my favorite one is 54321 so you list 5 things you can see around you 4 things you can feel 3 things you can hear 2 things you can smell and 1 thing you can taste mints whatever you have on you that you can put in your mouth and just describe the flavor to yourself in your head happify is a good app for anxiety so is flinch I use them daily