No way! 13 days of being holy and pure! That's a huge accomplishment, and nothing can take that away from you (unless you say that you regret having done it). It's like a solid investment in a bank that's there for life (and beyond), and no recession can hurt it!
Of course it hurts when you fall. And naturally, you feel down about it. But I think you have a right (even now) to feel good about holding yourself back for 13 days - yes, to feel proud of your accomplishment! 13 days of bringing kedusha into the world, 13 days worth of effort, making this world into a better place! The chofetz chaim says regarding lashon hora (and I think the same would apply here) that someone who restrains themselves even for an instant merits reward that the angels cannot fathom. That's even if after that one instant, he goes on to say the lashon hora. Now, imagine if he held himself back from saying lashon hora for 13 days?!
Your nisayon now is to not let the yetzer hora get you down, to move forward and start again, figure out what you can change to make this time even more successful.
We're all with you, cheering for you...