I read it about 6 years ago, when i was a young'un I can recall it being about a young girl, area hit by chemical weapons or something so it's all ash-y outside etc. In a jouse with her mum I think and sister. They have a dog but I think they get the farmer to shoot it. The young girl gets supplies from some farmer and churches. She goes to like a bunker where it's safe, but it is old and eventually they find out they can survive outside. Go outside and she finds people that have adapted to the world, and they are, basically, mutants and one of them was someone she knew I think. I don't know, my memory may have changed a few details. but please if you know what book I am talking about tell me! I have been desperate to find out for ages as I really want to read it again. Thank you xx