I've missed a few pages so forgive me if it's been brought up, but I'm half-thinking that the bloated walker WAS Lori, and Rick's addled state kept him from seeing her as one.
Her body's abdomen would still have been distended after the birth and if Carl had been unable to shoot her, zombie Lori could have reanimated and dragged herself to a sitting position (which seemed to be where the blood trail led) where Rick ultimately found her. His subconscious would have made her look like a walker unable to walk with a belly full of Lori, and he re-killed it accordingly.
His hallucinatory state could then extend to the phone, assuming it's not the Verizon guy.
Mark
Her body's abdomen would still have been distended after the birth and if Carl had been unable to shoot her, zombie Lori could have reanimated and dragged herself to a sitting position (which seemed to be where the blood trail led) where Rick ultimately found her. His subconscious would have made her look like a walker unable to walk with a belly full of Lori, and he re-killed it accordingly.
His hallucinatory state could then extend to the phone, assuming it's not the Verizon guy.
Mark