This problem started for me once schools opened back up after covid-19, I can’t go through my day without thinking about death. Even seeing raw meat can freak me out, and I work at a grocery store.. 
I’m not afraid of pain, I’m actually comforted by the fact that I will more than likely embrace death in the moment, and I won’t remember my death. I’m afraid of losing everything else, my memories, my life, my family, death is inevitable, but I want to have my memories forever. 
I think about death in a way that I’m already dead, everything I see will turn blank, just like someone wiping your memory, you would never know it happened. 
I personally don’t believe in an afterlife, I’m an atheist, I’ll probably get adjusted to this other time but just hearing “you won’t remember” is the exact thing I’m afraid of, and it’s infinite!