Why do we specifically count the 49 days leading up to Shavuot? We do not find this concept by any other chagim in the Torah. Additonally, if individuals already gave their omer offering the day after the first day of Pesach, what does it mean that we count the omer? What are we counting exactly?

The Midrash writes that when someone knows that a special treat is coming he fills with expectation and couts the days till the treat. That is what we do during the Omer - we count the days up to Matan Torah the recieving of the greatest of gifts - the Torah. Rabbi Ro'i Margalit