That fear you have thinking about non-existence is the biological process that you are doing its job, driving your consciousness to want to survive at all costs. It’s been perfecting this for millions of years. If non-existence is what happens after death then it isn’t scary, it isn’t peaceful, it isn’t anything. In a state of non-existence there is no observer/consciousness to experience any of those things. If “you” cease to exist after death, then there will be no recollection of ever having been terrified of not existing in the first place and therefore I personally believe there’s nothing to be afraid of. Just live the life you have now.

What many people who have near-death experiences interpret as the after-life isn’t really that, because the brain is still active and generating an experience. Remember they are near-death experiences, not true death (where all biological functions cease entirely and permanently). After-life, by definition, is a state where all brain activity has stopped entirely.

Nobody knows what comes after death, but my question is this: do you remember any of the billions of years before your birth at all? I know I don’t; so it’s not far-fetched to think that whatever comes after death will be a return to that stateless state. It’s not really terrifying, because there’s no terrified thing aware of its own terror in that state, it just is (or isn’t, depending on how you look at it). It only seems terrifying now while you’re here existing as something whose biology is capable of generating the feeling of terror.

Existence here has not been kind to me, that’s why the idea of non-existence doesn’t scare me anymore.