Woe to Us on the Day of Rebuke

The Midrash tells us that Yosef's brothers were overwhelmed by his rebuke, yet the Pasuk says that all that he said was, "Ani Yosef- I am Yosef".  Where is the rebuke that the Midrash refers to? 

This teaches us that rebuke is not verbal castigation that we have come to see it as, rather it is making a person aware of the the fact that he has erred.  When a person realizes that he has lived his life with a totally mistaken perspective, then rebuke has accomplished its purpose.

from the Sefer "Reb Chaim's Discourses" THe shmussen of the Mirrer Rosh Yeshiva Rabbi Chaim Shmulevitz ztl  page 98