What if the rapture doesn't occur?
I would curl up my toes and die. No, seriously, I would do the same thing that I do now every moment that the rapture doesn't occur. I would do my best to serve God and my fellow man by seeking His will for my life and then doing it. I would proclaim His good news to those who don't know it and to those who don't believe regardless of any personal suffering.
In 2 Peter 3:9-14 we are challenged to endure though it may be a long time before some of these prophecies are fulfilled. We are told to: have holy conduct and godliness, look for and hasten the coming of the Day of God, look for a new heaven and new earth, to be forward-looking, diligent, in peace, without spot and blameless.