A childhood belief about periods

once, i saw blood in the toilet after my mom got up from it. when i asked her about it she said "my egg broke"
Later i learned that a human's egg is very small, like a period in a book. I wondered how so much blood could fit in such a tiny egg.
I hoped it didn't hurt when the egg broke. Whenever i had blood come out of me it hurt. Later i learned, that yes it does hurt when your egg breaks.