Am i entitled to overtime pay or are my employees?

For the last 4 years or so I have been managing a retail store in which the company requires me and all of my full time employees to work alternating 5/6 day work weeks. My pay is comprised of a base salary, personal commission, and a percentage of the store's total volume whereas the full time ociates get paid only wih a weekly base and personal commission. I am required to sell the exact same amount as my employees and left with little or no time to actually manage my own store. The DOL website states that in order for a manager to be exempt from overtime laws he/she must spend a minimum of 50% of their time actually doing management related duties. Please help