Has anyone else experienced lower back/spine weakness within the first month postpartum?

It may be the muscles in my lower back even, I’m not sure. But when I carry my baby if I lean backwards it feels like my lower spine may crack or disintegrate 😅. I know that’s a dramatic description but i don’t know how else to describe it.

It only feels weird if my back is arched forward in any way. Like right now I’m on my stomach in bed and if I lift my butt my lower spine feels sore and fragile.

The pain is if I stand like these women: