Aren't we fucked nonetheless if there was a nuclear war?
Well, that really depends on where you are. If you're in a big industrial center, you're screwed, but everyone in Wyoming wouldn't really have any problems, eh? I'm assuming in this topic that you weren't screwed from the get-go.
The reason I brought this topic up was because I read the book Alas, Babylon two years ago and I just remembered it while reading Brave New World. In AB (I'll call it that from now on), the main character actually sets up a community with his neighbors and family and manages to stay alive for over a year after the big nuclear war.
AB also makes it realistic - the main character really screws some stuff up early on. He had advance warning that the war would probably come very soon, but when he went to the store to get supplies he forgot really essential things like fresh water, flour and salt, etc. I suggest the book strongly, if you haven't read it yet.
The point I'm trying to make is, I'm pretty sure that life as we know it would change drastically if a nuclear war broke out, but there isn't any reason that people couldn't continue living (if they weren't in a blast area, at least).