I also wonder if the way your downplay the significance of death, and don't fear it as you say, is contributing to her increased worry. Almost as if she can't trust that when you say nothing is wrong, you are indeed 100%. I needed my Dom to stop trying to be superman for me, and admit to me when He didn't feel well, even if it was "I'm really tired tonight, I think I'm going to go to bed early." Hearing him take care of his physical well being, and not try to hide it if he was doing so great one, allowed me to trust that He was taking care of himself.