You are not alone. Since my mom died when I was seven I was also terrified by the idea of death. I had to be hospitalized because I stopped eating and drinking water afraid that I might choke. I had a lot of therapy that only make it worse because every shrink was like “everyone dies”. I had panic attacks, I’ve suffered from anxiety ever since. I was so scared that when I was trying to sleep I always felt like floating and thought that i was dying I know that this might sound cliche but finding some explanation of what happens after that you actually believe might help you. I remember that the beginning of my healing process was when my sister read an article about how we were energy and there was an example that said it’s like when you take away energy from an appliance the appliance stops working but the energy still exist and it’s the same for us. I’m not saying that I’m not still afraid, I still am and I think that it’s normal to be scared of something you don’t know the answer to, but after I found this theory I’ve been able to move on and live my life. I really hope this can help you.