Every time you Google a symptom and feel relieved when it says "probably benign," you've just reinforced the pattern. Your brain learned that checking equals relief. So it's going to make you check again. And again. And again.
Health anxiety feeds on reassurance. The Googling, the ER visits, the checking your heart rate, the pressing on things to see if they hurt. Each check provides about 20 minutes of relief and then the doubt creeps back in. "But what if they missed something."
The fix is counterintuitive: stop checking. Notice the symptom. Resist the urge to Google. Sit with that shit, and show yourself that nothing bad is going to happen just because you stopped working yourself up. Well… nothing other than you'll start to simmer down.
It's uncomfortable as hell. It also works really, really well.
That's basically what treatment for health anxiety looks like. Deliberately not doing the thing your brain is screaming at you to do, and discovering you're fine anyway.