work stress

I've recently discovered that my boss cut out the 2 hours or so of overtime I worked last week. Not just removed the time-and-a-half aspect of it, but totally removed it. I don't get time-and-a-half and I don't even get regular time for it either. Zilch... zero... nada. Basically they stole 2 hours (and probably more) from me. I've contacted HR but they gave me a very vague statement saying no one is guaranteed overtime. OK fine but I worked my ass off during that time. I deserve to be paid for it. if they don't pay me for it, they are stealing from me. If the tables were turned and I clocked in and then went out to see a movie for 2 hours, I'd be terminated on the spot for stealing from the company and rightfully so.
I'm still trying to come to terms with a lot of the limitations that have been placed on us. This is yet another I have to deal with. Anyone know a good labor attorney?