Has anyone else experienced familial hypercholestromia

I used to eat the carnivore diet but sometimes I wouldn’t completely avoid processed foods and deserts and recently I had a blood work test and I’m not obese or anything but m6 family might have a history of high cholesterol and idk wha5 to do about it I got blood work done and my total cholesterol was like 356 and ldl was like 283 or smth very very high and so my doctors were very serious a bout it and I tried to argue and tell them how nutrient dense the meat is and stuff and he wouldn’t want to argue me t all and just told me this story about some rats with scientists giving the rats lots of saturated fats mostly coconut oils and they ended up dying with their hearts completely stopped idk recently I’ve been having chest pain like sharp and randomly sometimes it comes while I’m running or working out I know I do have a family that struggled with heart disease and heart attacks and stuff but I don’t know what to do the doctors are saying I’m gonna die and stuff and told me if I don’t stop this diet I could have heart problems later in life right now I’m 16 and like 3 months old and I don’t know what to do and basically my family has heart health problems