Reb Natan tells us:
Even a drop of good is never lost! Never! Our Sages teach, “If you’ve searched and succeeded in finding, believe it” (Megillah 6b). Why, believe it? If I’ve found, then I know it. What’s the point in believing? But, this is the point. No matter how much you seek the good, you may think you haven’t yet achieved or attained any. You might feel yourself even more distant from your goal than you were before you started. With this in mind, our Sages specifically taught, “believe it!” Believe that you’ve found some good, even if you can’t see it! (Likutei Halakhot, Birkhot HaPeirot 5:1,2).
From Crossing the Narrow Bridge, by Chaim Kramer