I sympathized with Shane when Dale lit into him. How the fuck is he supposed to know the old goat has the hots for Andrea? Shane probably thinks someone's Dale's age wouldn't be interested in sex unless he's been sending Glenn to town for Viagra. 
As for Lori, her angst is understandable. She personifies the predicament that everyone is in: are their lives even worth living now? Everyone else is pushing it aside by denial (we can cure the zombies) or just focusing on what's right in front of them (find Sophia, learn to shoot, have post-zombie-fight sex in the front seat of a Honda Civic...) But being pregnant means Lori has to confront what everyone else is strenuously trying to avoid.
I have a feeling Carol is going to be zombie-chow before they ever find Sophia. That will lead to some of the gang arguing that they should abandon the search since Sophia's mom is dead - a horrible attitude to take, but of course Shane will be in everyone's face about it. Shane and Daryl will fight about it, since Daryl more than everyone else will want to keep looking.
After they've actually given up, they will stumble across Sophia by accident and will have to pretend that they were still looking for her all along. This provides a new source of secret guilt, and finger-pointing blame based on how strongly or weakly each wanted to keep searching - and raises the issue of who will raise Sophia?
Carl will want to adopt her as a sister, but since it's a foregone conclusion that Lori will have pregnancy complications (maybe she didn't throw up all the pills?), she won't be able to be a good surrogate mother.
So that leaves Andrea, who will come to see Sophia as a surrogate Amy. If Andrea and Shane become a couple, that makes Shane - the guy who wanted to leave Sophia for dead - as daddy. That will infuriate Daryl, who of course can't tell Sophia the truth since it would traumatize her.

As for Lori, her angst is understandable. She personifies the predicament that everyone is in: are their lives even worth living now? Everyone else is pushing it aside by denial (we can cure the zombies) or just focusing on what's right in front of them (find Sophia, learn to shoot, have post-zombie-fight sex in the front seat of a Honda Civic...) But being pregnant means Lori has to confront what everyone else is strenuously trying to avoid.
I have a feeling Carol is going to be zombie-chow before they ever find Sophia. That will lead to some of the gang arguing that they should abandon the search since Sophia's mom is dead - a horrible attitude to take, but of course Shane will be in everyone's face about it. Shane and Daryl will fight about it, since Daryl more than everyone else will want to keep looking.
After they've actually given up, they will stumble across Sophia by accident and will have to pretend that they were still looking for her all along. This provides a new source of secret guilt, and finger-pointing blame based on how strongly or weakly each wanted to keep searching - and raises the issue of who will raise Sophia?
Carl will want to adopt her as a sister, but since it's a foregone conclusion that Lori will have pregnancy complications (maybe she didn't throw up all the pills?), she won't be able to be a good surrogate mother.
So that leaves Andrea, who will come to see Sophia as a surrogate Amy. If Andrea and Shane become a couple, that makes Shane - the guy who wanted to leave Sophia for dead - as daddy. That will infuriate Daryl, who of course can't tell Sophia the truth since it would traumatize her.