I don't know what happens after death, so i can't formulate a belief because belief requires some certainty. I'm inclined to think based on information we've gathered empirically with our senses that you decompose, and life goes on around you. However, i cant be so foolish as to think that i KNOW this. i haven't researched fields like parapsychology. the idea that there are multiple dimensions shows that reality is MUCH stranger than we know.
My mind pretty much follows a circle of thought from existence to death so much that i sometimes get depressed to the point of inactivity. then some other days it switches off because i get back to myself and endorphins and all that shit, but any given moment it creeps up on me agagin. It weirds me the fuck out that one day i won't be able to see with these eyes, to feel the wind, to consume water, to hear music... i just won't exist at all. GONE. just a dna vessel that's served its purpose. I have a suspicion that people are really not aware of death, or have become so engrossed in their ego and the biochemical prison of their body that they feel immortalized by their accomplishments.
I definitely agree lots of people won't feel so tough about death when they have to face it at last. In my view it's great that these questions are tormenting you, because keeping it bottled up is a step in the wrong direction.
So for the first step I would say to pursue Truth ruthlessly, wherever it may lead. If reality turns out to be a monstrous creation then you can become the meanest mother fucker and seek to do evil. Lots of people do that. But maybe you'll find a different path. That's not for me to decide, I just want to see people go, go down some path, just not stagnate, because in fact change is the only constant so if you think you're standing still then you're regressing in the worst possible way, you're denying logic itself, learning to live out of your mind in a weak world of disgustingly indulgent make-believe, and as you age you start to forget things and you get senile real fast, very spiritually unhealthy.
As a catalyst for the first step, there's always something for me to point to. The only thing holding you back is an illusion! In reality you're already falling into the vortex, you just don't know it yet. You say: "I don't know what happens after death, so i can't formulate a belief because belief requires some certainty." But come on man, you're KIDDING yourself. How do you know that what you're experiencing isn't just all a dream in your own head? How do you know I'm a real person at the other end of this interwebz who's replying to your thread? And also, how do you know that reality is going to continue, so that there's even a point in making another reply for 'me' to read tomorrow? Certainty is absolutely the key, and the key is to realize you don't have it at all! You fear of death is based on premises which are totally unfounded in the first place, in the sense of existential dilemma, and if you want my advice, only by taking a great big step back and tackling these broader issues can you make true progress in life and, indeed, also with this question of death.
I mean hell I think you realize there's no answer to your question, right? It's pretty fucking straight forward, total non-existence is the most horrible idea imaginable, and the very thought that's it's a possibility when you die makes you furious. So come on, take a step back, and consider that you have NO idea if the default state of things is mortality or immortality. You have NO idea about anything. For all you know you could be living in a hell dimension, or the situation could be really dire and demanding your immediate attention. YOU DON'T KNOW! If you can manage to discard all your safety blankets, all the assumptions society tells you about what's real, then you can confront the real dilemma of existential uncertainty head on. And indeed then when you find the answers they won't be marginally interesting to you like they would be for an armchair philosopher, no, to you they'll be your whole foundation because you have nothing else. You can't get it if you're not ready (willing?) to see it.
So I say take a dive off the deep end into the vortex. And I realize I can't expect you to believe me that you'll be OK, that everything will be OK in the end. All I'm doing here is MAKING you dive, because if you've grasped the logic of my words here, then already you've seen some things you can't turn away from anymore! Or that is, you can turn away from it if you want, but I guarantee it won't be healthy for you... hahaha!