Not existing is not terrifying at all. What were you before you were you? So you won't know or experience anything anymore - just use the time you have to do what you want in life, it's chaotic, sure, but this is the natural order of things. I actually find peace knowing that all the crap they taught us in the bible is false, and therefore I don't have to put up with the negative things life can deal you after passing.
It's also food for thought that not existing after death is more than enough reason to do the things that would make you feel good about yourself while you are alive - visit people, make friends, have some fun, do some good work, etc. I have a bucket list, sure, knowing I won't get to do all of it probably, but it's a fun ride, nonetheless.
