What are my legal options for being wrongfully demoted?

I have been with my job for over 5 years now. In the company there is a position right under supervisor, called a floater. I, along with a few others, was a floater. My supervisors boss demoted me without reason, just said I was a waste of money basically. The day of my demotion, I asked if all other floaters would be demoted, I was to yes, because they were doing away with the "floater" position. For three weeks now I have kept tabs on the other floaters (writing everything down), and they all still have their position. I was working a full 40 but now I'm at 13 hours a week and from my understanding, I lost $.50 on the hour even though I was told my pay would stay the same. I have no proof of this because I have to pay to receive my check stubs. Do I have any legal options since I was the only floater demoted?