Mondo, can you get one of those study abroad internships or whatever you call them? Those are basically licenses to take time off and travel while still being classified as a student still. If you can't do that, I'd take hearts advice and take some easy classes.
Also, I know this is risky but have you tried talking to your parents and telling them the situation that you are in? I know they could possibly feel disappointed and you may be deathly afraid of disappointing them, but I think they'd end up feeling the need to help you get things together if you tell them that you are having a hard time, especially if it means a lot to them that you do well. I find it hard to believe that a parent who is paying for a Duke education for their child would push them further down when they are feeling down. This would be better for your life in the long run.