I used to think fear of death was just existential and normal. Then I realized normal is to actually have a lot of filters I don't have. People don't seem to hear sounds I hear, see things I do like details, they just live in their own happy bubble. Living in that bubble, is normal. Not thinking of your own passing, is normal. Strong fear is not life saving, it is life poisoning and crippling. Not normal. It is just the same as other panic and anxiety stuff, it is abnormal and it can be treated with meds. You'd say but death is real, so you shouldn't treat feelings about it. Well if you are hit by a car and break bones, the car is real, so you shouldn't have pain meds?

I don't believe in an afterlife and it really messes me up sometimes because I am one of those who need a belief in it. It's a quite hard life sometimes and it does create extra anxiety, more than I normally have. There are tricks to break the cycle of thinking about it. There are comforting things you can think about. I also use that stuff. And medication, because I'm quite a sensitive person.

There is something in my mind that just decided against an afterlife. I have seen a lot of evidence of an afterlife and I still don't believe in it. It is like I'm just programmed like this. There is probably something pathological about that as well, like I need 100 % proof before I can believe in something. Usually people believe in things (less serious things as well) with loads less proof.

Anyway, I feel your pain. I know what used to help me the most when I was a kid and got freaked out by this, was talking with others, the few I had that were OK with the subject. Maybe you also feel a little better connecting with others over it. Take care.