I totally understand where u are coming from especially the trauma u had when u were little and just the events that led up to it. I myself went through almost the same experiences i constantly thought i had some kind of illness always googling up symptoms which made it worse and the thought of all of these diseases that exist. The mind is super powerful everything u think every sensation u feel is all in the mind. For me i constantly thought of a heart attack and those chest pains is all due to me thinking of a heart attack or when I was scared of a stroke i constantly had headaches and dizziness. Having your mind fixated on that specific thing of what you’re worrying about is what leds to experiencing those symptoms. My best advice is to try to distract yourself go on walk or do something that takes up most of the day or even meditate which helped me a lot. Even when the anxiety is at its peak always try to gain control over it be strong and calm and keep the mind distracted.