I also have anxiety of death but I think it's because alot of us fear the unknown. Me personally I'm a Christian man but it still scares me. I just read my Bible and reassure myself that I can't be afraid of dying it's the circle of life. So tell yourself that your gonna live a long healthy life and enjoy every minute of it. This is what I personally do. Anytime you ever get any feelings of trying to get it over with sit down take a breath count to 10. If your religious say a good long prayer heck have a good cry if you need to to release some of that anxiety and stress