The Alter of Slabodka, Rav Noson Tzvi Finkel, offered this bit of advice to his students. At all times a person should keep in one of his pockets a note that reads “Bishvili nivra ha’olam — For me the world was created” (Sanhedrin 37a), while in the other pocket he should keep one that reads “Va’anokhi afar va’eifer — But I am dust and ashes” (Bereishis 18:27).
Bishvili nivra ha’olam speaks to the world as I experience it. That was customized just for me. And it contains all of my potential. However, with regard to the shared universe, all that exists is how much of that potential I actualized. “va’anokhi afar va’eifer“. The Alter recommends that one have a pair of dialectical views about one’s self-worth. The first speaks of one’s potential, being in the Image of Hashem. The other, of what one has actually accomplished.
His work, Or haTzafun is hard to obtain, so I cannot look up where in that text I found this idea.
He could have heard the core idea from Reb Simcha Bunim of Peshischa and elaborated on it in a manner consistent with some of his teachings' central themes. Or perhaps both quotes came from a common earlier source.