You are hardly alone. Many of us who have left the faith of their childhood have expressed similar sentiments. The author, Julian Barnes, is noted for having said, "I don't believe in God, but I miss him." I kind of felt the same way as a kid about Santa Claus.

"...spending an eternity in a heaven or hell based on how you lived your life sounds like a crock of shit."

What's an even greater crock of shit is that the Christian tradition allows for one who's lived their entire life as a criminal, rapist and murderer a free pass into heaven, so long as they confess, prior to death.

It is quite natural to fear death, and as we near it, to 'rage against the dying of the light.' But when one considers the state of one's consciousness, prior to birth, death is very much the same thing.

"Wtf is the point of existence."

Quite honestly, when one gives up on the concept of heaven or an afterlife, one is free to make the most out of this life, and make good decisions for those who come after. I have come to the point of view that it is the very belief in a paradise or the hereafter that diminishes the importance and meaning of this life. After all, when a person views this life as a waiting room for what's to come next, how vested are they really in this world? The point to our lives is what we make of it, not what others dictate.