Personal support though sacrifice
How much of a set back do you think this was??
My magic number is two weeks. For some reason, that 14day mark seems to lead to a break in...sobriety? Detoxing? Cleansing? I dunno what the terminology should be, but I do know that it never helped me to feel shame and dwelling over it. Take a moment and reflect on what you did, what you were expecting to happen, how it felt during the moment, how you felt after the effects wore off, and how you feel mentally and emotionally after breaking your "fast". Then relax a bit. Take a breath and know that, while it's did happen, it doesn't mean you're back to square one. You'll NEVER be at square one if you rebound back to that mindset of "I'M GOING TO GET/STAY CLEAN!"
You're not the first person to have a "moment of weakness", but that's not the same as relapsing. In fact, it's not even a moment of weakness. It was really a personal experiment to see what would happen. The results are different for everyone, and that moment was a chance for you to learn something about how your mind and body reacts to "the poison" after so many days clean, or into detoxing. That's all. Just an experiment. Now you know something you never gave yourself a chance to know until now. But! It's behind you. It changes nothing about what you want: Absolution. Maybe it set you back a day/week, or maybe it did nothing. It doesn't change the FACT that you WANT to move forward with your life: A life without addiction/dependency on a specific substance in your life because you know you'll be better off. YOU KNOW YOU'RE BETTER OFF! So, don't dwell on it.
Also you may not realize this, but by you not allowing it to suck you back into the abyss you're setting a positive example for the rest of us who get down during our "moments of weakness". Because you're proving that idea is a misconception. Anyone that sees you "get back on that horse" will see your example, and think "Yeah, look at how s/he didn't fall back into the Abyss. If he can get back on that Horse, then so can I." They won't tell you that, they'll just do it!
tl;dr: You're not relapsing, you're setting a bold example through personal sacrifice. People feed off strength. People feed off examples that they can intimately identify because they've been there or are simultaneously going through the same struggles. Thanks, for the support (even if that wasn't your intention).
Source: My brother and I feed off our positive resolve (when battling opiate addiction) more than focusing on the supposed negatives. We never say, "Well, you're so weak for such and such." We ALWAYS say, "Damn man, you came back from 'THAT'?!?! So, can I (because I know you're a strong person too). I'm proud of you"