Take a deep breath -- look how far you've come from where you started. This may be a step backward, but it doesn't mean you're out of the race yet!
One thing that helps me when similar things happen is for me to sit down and look at *why* I've been gorging myself. Is it because I was under stress, and didn't have a good outlet for it? Was it a way to "reward" myself because I'd been neglecting to give myself any non-food rewards lately? Was it because I was eating too few calories, and my body was starving, so I need to up my calories a bit? Etc. Sometimes, just seeing *why* I've been overeating helps me to prevent it from happening again...and motivates me to get back on track.
At any rate, try not to be too discouraged. It happens to the best of us. The good news is that it's never too late to try again.

Good luck... *positive thoughts*