What would happen if your country was nuked?

I read a thread about this on the Cyber Nations Forums (off-topic part). A lot of people said that they would die because they lived in or very close to a major city. Other people said that they would get a gun and try to fight the other country's army if they invaded. There was a debate going on about whether retaliating after being nuked was a good thing to do. Someone said that you were going to lose either way and that retaliating would just get more people killed. Another person said that you should retaliate to get revenge on the country nuking you. One (or several) person/people said that you should nuke the country to take out a country that launches first-strike nukes.

If my country was nuked, I would flee to Mexico. Hopefully, Canada would stay uninvolved. It probably would, since it doesn't want to be destroyed for no good reason. I would probably walk there because I don't know how to drive.