How I deal with no afterlife

[SuperMarioGamer]

So, animals don't experience joy?

"my ability to cherish this life is always being hindered by the idea that I will just forever decay one day when I die."

This bit doesn't seem sensible to me. In order to cherish something, it must necessarily be temporary. We cherish things when there is a prospect of losing those things. Perhaps you rather meant "enjoy"? Though if that's the case, then do you just walk around aimlessly proclaiming, "Oh, woe is me! Woe is me! How fleeting this life can be!"?  If so, I'll just hearken back to Expired's post, "The way to deal with no afterlife is to realise that you had no beforelife", which ultimately derives from Mark Twain; “I do not fear death. I had been dead for billions and billions of years before I was born, and had not suffered the slightest inconvenience from it.”

Don't allow unknown outcomes to rule your life. Enjoy it while you still can.

You don't seem to be interested in much of an afterlife, but more of immortality, which I can grok with. Immortality in this life, from a modern perspective, would be nice, but I don't see how immortality in some other form of life is appealing at all.

I am a narcissist sociopath which means that the only thing that matters to me is me being happy, getting what I want, and living forever with no misery and no suffering in my life.  It would be a life all meant for me to be happy and enjoy.  I wouldn't have to worry about any problems at all if such a life were real.