Hershel says Judith is how old?

In the Suicide King, when Tyreese and Sasha,Ben, Allen are there, Hershel says Judith is a week old. 

How is that possible, doesn't he mean two days old. Is it possible that Rick was in Lori's death place for 6 days.

I know this blog is kinda pointless, but I'm confused. If Judith is really a week old by there, then we need to chance the timeline.

Please tell me what you think.