Thanks jnorthrop.
I guess I should have added more detail. We've written out a full business plan, it's just very weak (knowingly). We've pitched a few different times and just finished up a Business Plan competition at our school.
It was a fantastic experience and we learned an absolute ton (a lot of it being how much we did wrong from the start, but still very valuable). It's just so hard to tell the difference between "quitting" and spending your time more wisely, i.e. on a new idea.