Over the course of history, the Jewish people have endured unspeakable suffering. From Churban to pogrom to exile to Inquisition, all leading up to the unimaginable losses during the Holocaust, we have plenty to mourn for. Yet, when we look at the Jewish calendar, while Chazal set aside Tisha B'av (and the Three Weeks) as a mourning period for basically everything else, we devote almost five full weeks to remember the deaths of Rabbi Akiva's students.
How can we devote so little of our calendar to the Holocaust, and so much of it to a seemingly smaller tragedy in the course of Jewish history? The answer to this question lies in a deeper understanding of why we mourn during Sefirat Ha'omer.