Are you really ok with nothingness after death? Because im not.

I'm 14 and the thought of my life ending and thats it, no feeling, no afterlife, no thought, no body, is far more scary to me then an eternal hell. It makes me feel so physically sick and i dont know what to do about it, people just say im 14 and i shouldn't worry about it, but i really can't stop it. I think people who would throw away an eternal life are stupid because i dont know if ill ever be able to accept the finality of death. I can't possibly know how nothing feels but i dont want to, it's genuinely sickening to me. This is running my life and i've been losing sleep over it for 2 years.
Any advice?