AAA i just cant stop thinking i have this

Question

Im 25 years old i have random racing heart and it , palpatations, i have been going through this for years, i had high cholesterol as a child im not sure if its still high, and most recent for the last 2 months i have felt my heart beat in my abdomen from my middle rib down to the top of my navel more to the left side. I unfortunately looked it up and literally scared myself its only when i lay on my back or stumach. I got a ekg as well as a 48 hour heart moniter all checked out normal. I had a chest CT down for dissection which dr everything was normal. I had adominal pain so they did a CT scan of my stumach and all she said was a pit of constipation but everything looked normal. These are 3 seperate drs all saying im fine. I went to my GP who could feel my heartbeat as well and informed because of my size 5'7 130lbs that it was normal to feel my pulse in my stumach. My grandpa has AAA currently and still living with it until its reached its size, i use to be a smoker but recently stopped about 3 weeks ago, my GP as well as all the other drs just informed me its anxiety and i need to relax . I just cant get over it i need more piece of mind i dont have this.