What if the rapture doesn't occur?
The Rapture will happen, but we just don't know when (1 Corinthians 15:51-52; 1 Thessalonians 4:16-18). When God promises something you can count on it coming true. He also told us to "occupy" until He does return (Luke 19:13). It is always best to keep busy serving God. Proclaiming the gospel is one thing all believers are commanded to do (Matthew 28:19-20). Pray for His will for your life and He will show you how best you can serve Him in other ways as well until He calls us home.