Day 158 - LESSON LEARNED?????

Well I have done it again!  This morning in my eagerness for sewing I made 2 blocks of the strip quilt and completed them only to find out that they measured 8"x8 1/2".  Tonight I have been sewing for an hour and just trimmed my blocks - 4 new ones and they are 8" x 8 1/2".  THEY ARE SUPPOSED TO MEASURE 8 AND ONE HALF INCHES BY 8 AND ONE HALF INCHES!!!!!  arrrgh.