I relate to this. This is the problem with dying of natural causes. I think people have this fantasy that they will suddenly and painlessly be struck down by something. I guess it could happen like that. One massive heart attack and out. There are plenty more nasty and insidious ways to go though...
The first time I had a gallstone attack, I thought it was a heart attack. Like this terrific clamping feeling in my chest. Excruciating pain, difficulty breathing, panic but I thought- this is it and I'm ready for it! I'm NOT phoning for an ambulance. I kind of crawled to the window and watched the world go by a bit. But, 30 mins later, then 2 hours later, I realised it was subsiding. It kept happening after that and I used to curse God- in case there is one- 'Stop with the foreplay, stop f'cking about and kill me!'
What with my reluctance and how useless the NHS is, I had 12 or 13 more attacks by which time, the pain hadn't subsided for 2 or 3 days and I just couldn't hack it anymore. They finally diagnosed it and said a stone was blocking the bile duct. I maybe would have died of that eventually but it's the not knowing what you've got, how bad the pain will get, how long it will go on for and not even knowing whether it will kill you. All you want to do is get out of pain in the end. I quite understand. I hope you are at least out of pain now but I get it, it's not the result you wanted.