that's because the op stated his/her biggest fear was if there was no afterlife.
if you don't exist, what does it matter? there is no consequence ether way.
what if there was an afterlife that was burning in hell for all eternity? some people believe that too. would he/she rather choose that or an burning in hell for eternity or perhaps being born diseased, deformed and then starving to death? life itself does not necessarily mean that it's good. i think people who don't see this are the ones who have relatively what is called normal lives with occasional ups and downs. they don't realize just how bad living can actually be depending on one's circumstances. so they see their current life as the end and be all and are very attached to it and afraid of losing it.
there is a natural fear of the "process" of death because it is usually unpleasant and also we fear the loss of control and the unknown. also, some fear leaving those they care about behind or not being able to be there for them or for them to suffer or grieve over them and vice versa.
still, though if death really were the end. in some way, it's not that bad considering at least they are not suffering anymore and one day everyone will die. it would be a lot more harrowing if there was an afterlife and one didn't know what happened to their loved ones and where they went and what state they are in.