Someone wrote on the forum how they had taken a number of steps to try and stay clean, but after just 2 days an unexpected test came up and he fell. He asks: I just can't understand why G-d would add on this test after he sees I'm making the effort and setting up fences?
Often Hashem sends us tests we can't resist precisely when we are putting in effort and because we are putting in effort. (Like when Moshe first approached Pharaoh, he made the work even harder!) Perhaps Hashem does this to help us progress on our journey even faster, when our fall helps us realize a few things:
1) The fences we put up are not adequate. We need to reassess our battle-plan and make even better and stronger fences.
2) It makes us think, "do I really want to change" or am I just "forcing myself" by making lots of fences? (which ultimately won't last).
3) It makes us realize our powerlessness and become more dependant on Hashem.
All three of these recognitions are progress. So ignore the fall, and take the "gift" of this new awareness into your arsenal! :-)