Timelines, the show is about a week to two weeks in real time, so if she's already pregnant there is no way that she could possibly already be shows signs of being pregnant from her night with Rick when he returned. She was clearly already pregnant when he arrived. It will be interesting to see how Shane handles this and this might be what drives a wedge between Carl and Shane.

 

Yeah the timeline is off, but the right think to do was to say it was his. The problem is, what if he figures it out...it would only make things worse.

 

if I had such a husband who loved me and my boy like that, care about us and only thought about keeping us alive, I could say the baby, tree, car or anything else was his.