That nothing matters is, in its own way, entirely liberating. Nothing matters, so do what you care about. Try not to make other people's experience worse, because you're not an asshole, but otherwise be free.

Alternatively, think of it like this: there was a vast ocean of time that passed before you were born, and you don't fear it. There will be a vast ocean of time after you are dead; don't fear that either.

Your continuity will be interrupted. If you've ever had a bad fever and lost time, or been blackout drunk, or gotten hit on the head, or whatever, you've already experienced interruptions of continuity. And you're only aware of them after you wake up and have to put it all back together. An interruption that you don't come back from is also one that you never actually have to deal with.

For me at least,I find that I don't fear death so much as I do resent it. "Ever since I first understood the weakness of my flesh" and all that. If I could trade my pathetic flesh prison for something eternal, I would. I am my mind, my thoughts, the continuity of my consciousness, not this decaying meat. I resent the idea that I will not get to experience all that I want to, but I don't really fear it.