We have had 3 major depressions and many recessions since 1797. It is the way it works. Periods of inflation followed by periods of deflation (like now.)
Now I am no expert on economics by any means. I have no idea how the world market will be affected or affect the US economy. But we are not headed for a collapse by any means. We have weathered much worse.
This chart should clue you in when you see the long list of panics, depressions etc...
List of recessions in the United States - Wikipedia, the free encyclopedia