Ask HN: How to Deal with Death Anxiety?

I started having frequent anxiety / panic attacks related to death about 2 weeks ago, and am not sure why. First layer is, I am afraid of my own death, mainly because I am afraid of the unknown I believe. Second layer is I am afraid of the impending doom of humanity, even if it is in a trillion years when the sun expands and covers Earth's orbit. Do any of you know coping mechanisms to deal with this? I am hoping I am not alone in this issue, because it is really scary.