There's really no such thing as the agony of dying. I'm quite sure that pain is shut off at the moment of death. You see something happens when the body knows it's about to go. Peptide hormones are released by cells in the hypothalamus and pituitary gland. Endorphins. They attach themselves to the cells responsible for feeling pain.
Why don't you start believing that no matter what you have or haven't done that your best days are still out in front of you.