I have read several articles on here as to if Lori and/or Carol are really dead. Here is my take. Some have pointed out that Carol is dead because of the flower Daryl puts on her grave and because we did not see them actively search for her. Some state that Carl must have shot Lori because of the flash backs provided and because of the fat bellied walker that had Loris hair in it.
1. Carl had a look of shame on his face when his father went back in. I think that is because he chickened out of shooting his mother. Otherwise, it would have been more dramatic (ratings) to have us watch Carl shoot his mother.
2. Her stomach has been ripped open, so as she is crawling around zombified she is leaving a trail of blood. The walkers are dumb, so I doubt the fat walker Rick found would have carried her off to hide his 'kill'. She must have made the movement on her own, or with help.
3. What's say the buldge in the belly wasn't Carol? Perhaps Zombie Lori and Fat Zombie had a tussle over Carol and Fat Zombie bit Lori, hence the hair.
I just find it too strange that they leave to cliff hangers like that in one espisode. Also, for those who say Lori must be alive because of IMDB, if Rick is going to go nuts and here her voice, she will still get credit for it. Plus I am sure some of Rick's future flashbacks will include his wife.