I haven't got paid a single saturday at work, what do i do?

I've been working at my job about 7 months, and I just noticed i haven't been getting paid a single saturday. Yes, it's my fault for not paying attention, but i over skipped the days/mis calculated and just noticed it. What do i do? I plan on talking to my payroll manager, but will i get the money i earned? If not, is there a way to get it?