My theory is that Amy's been unconscious and in labor. That's why I think it's showing she's not sure whether she's pregnant or not (because she's not sure whether the baby will live) and why Rory keeps saying "I'm a nurse." Also, why Rory keeps dying. It's her subconscious working through her worst fear.

I don't know the details of the storyline yet, just the big plot points, so I don't know how accurate my theory is.