Well, first things first, realize that you are in some good company. Of the folks I know that make beautiful bows, all have broken their share... many broke their first. And yours wasn't looking bad for a first effort. Sucks to do it in front of others... been their myself.
Second.... the next one will be easier. When you get the stave floor tillered, and you start scraping on the limbs, check the tiller very frequently, even if their seems to be no change... this way you start to pick up the minute changes that can become problems before they do. Also, I'd say to be careful to leave some wood at the fades (just outside of the handle...) and scrape slowly in this area until the bow is just bending. Read some tiller-alongs on this site, to see what others do... but more importantly, just make more bows yourself.
You will get there and make awesome bows. Keep at it.
Gabe