Having this conversation with a friend once, he told me what helped him.
Do you remember anything from before you were born? The hundreds of thousands of years before your existence? Did you spend it experiencing nothing all before you finally were born and began to experience something? Of course not.
You've already done a millennia of non-existence. It wasn't painful, it wasn't boring, and it wasn't scary. You're not something that started and will eventually cease to exist. You are something that didn't exist, and then eventually, you did. Sure, you'll go back there one day, but that's just it: you're not going to a new place. You've been there before, and it was fine, just as it will be when you're there again.