Reb Lo Levado (a.k.a. - Not Alone) - First of all, it's great to hear from you again!
Second of all, I'm glad to hear that you're still working on growing, and still planning victory!
However, I don't think the idea of "one day at a time" is about deciding each day to make a new commitment to being clean. I think it means that when you're faced with a nisayon, instead of thinking, "I can't do this, I have to be clean for the next 3 months," you say, "just for today." Or if that's too much, even "just for one hour." And then, an hour later, hopefully oyu've already moved on, or you can try to push it off again.
There are three major advantages to this strategy, that I can see (more experienced people can probably mention more). 1) it breaks time down into manageable chunks. Otherwise, we can think, "whoa, I can't hold off for 2 months!" But "just till tomorrow" works a lot better. 2) even if, after that day, you fall, you pushed it off for one day. That's one day without this huge aveirah, and the amount of kedusha that you bring into this world is beyond imagining. And 3) Even if, Ch"v, we fall, we know that we didn't just blow everything - we blew this one minute. But now, it's another minute, and we have another minute to be strong in, with hashem's help.