I'm Christian and have very deep beliefs in life after this. They bring some comfort to me on this topic. However in reading your words I suspect such a belief would not bring much comfort. I think you may have some anxiety issues that could be worth addressing.

Regardless of your personal beliefs there is next to nothing you can do to preserve this life beyond the brief existence you're currently enjoying. That's a hard pill to swallow but it's also a very freeing one. There is very little value in worrying about things totally out of your control.

If you have the means it might pay to talk to a therapist about this. You don't have to be unwell to see one. They can help guide you into developing new tools to deal with the anxiety and perhaps find some peace. At the very least talking to close friends or family might help.

Edit: just read the follow on in the comments. It looks like you have tried these suggestions. Sorry I don't have much else to suggest. Only this, if you worry to much about your end you could miss out on your now. Good luck figuring this out.