For former Marine and current Tennessee Titans fullback Ahmard Hall, 2011 was a year to forget. Unfortunately for Hall, he literally has trouble remembering the very end of his season because of the concussion he sustained in fourth quarter of the Titans’ final game. Hall, who served in the Corps from 1998-2002, got clocked by Houston linebacker Tim Dobbins on an outside run with less than two minutes to play. Watch the play here. The force caused Hall spin in the air and fumble, with the Texans recovering. Hall told The Tennessean on Monday that he was “clearing up” but…