National History Day and Flipped Class Doubts

This is my first year ever, being involved in National History Day. I have been aware of it since my teacher ed days. The focus this year for our school's Open House is history, so I though it would be a great opportunity to try it out (kind of like a Science Fair for history). I attended a workshop about it a few weeks ago at the University of Washington and that only got me more excited. I love the historical, critical thinking skills it develops. NHD's website has many great resources for teachers. I am getting students started on it now and even tried to break it down nicely for them, handing out a weekly timeline from now until the end of January (the due date).

In stress surveys I handed out this week (something we are trying to do weekly for each of our classes this year), many students were positive. Saying they were nervous about the project, but appreciated the break down I gave them today. However, just one student wrote some nasty words to me, including "why are we doing this, again?" Ouch, it stings.

So now I start thinking about priorities. How do I continue in my "flipped" classroom? I have been planning for the upcoming Middle Ages unit already. I wanted them to crowd source information and then in groups make a Medieval Game of "Life" or "Monopoly." But I'm worried. Is the thought of another project, granted, mostly in-class, going push them over the edge? Do I resort to passive, teacher-centered lessons? Is there some happy medium in-between?