I often think about childbirth, especially before bed, because of this…

I often think about childbirth, especially before bed, because of this I have trouble falling asleep. I'm afraid... It already seems like the roof is driving off, that's not normal. How can I calm myself down? I don't even know. It's getting scarier, because of the lack of understanding what will happen to me, I know it's very painful. But I'll be giving birth for the first time, so the unknown scares me.