I have vry similar worries.
But, just think this. Even though you will die, just live ur life amazingly!! Travel the world, be so successful. Be the biggest celeb in the world. Do crazy things. So when you die, know that you've lived the best life ever.
Don't live your life for heaven and afterlife, because ur here now and those things may never happen, but this is happening.
Also, you know that fear of death is a huge factor is Aspergers Syndrome. Not saying you have it. I have it though, and I know I do worry about it too and it is something that is what AS people worry about.
So remember just live your life to the fullest and be the best!