Facing a blank page is scary. It's the same for any kind of work, be it a blank sheet of paper, a blank canvas, or a blank screen. Even the small things are hard, like the blank page in your journal, or the blank box for a a new email, or even the blinking cursor for the beginnings of a new text message.
It's scary because you can't picture how it's going to turn out. You might have a vague outline of what it will look like, but you can't know exactly until it's actually there. It's like looking into a dark tunnel and only seeing the faint light at the end. You imagine the bumps in the road and the inevitable curves and twists you have learn to navigate along the way.
You've done good work before. You do good work consistently. But you still can't shake the fact that this time, it might not be good. Either as good as you want, or any good at all. That's okay though, it doesn't have to be. Great things come from when you make something and go back and make it better. They very rarely come out of thin air the first time (count those times lucky).
But haven't you found that every time you even try, it feels really good? When you're done with the first version of something, it's almost always good. It could be better, and it could be great, but it's always better than you think it was going to be. It's a victory. You took a blank page and turned it into something. Something useful, something beautiful, something unique. Savor that feeling. Look forward to that feeling. Use it to fuel your work. Your work on new things, and your work on making good things great. Know that anything is better than abandoning a blank page.