I Started Taking Hydroxycut About A Month Ago. My Last

I started taking hydroxycut about a month ago. My last period was November 5th. I missed my December period and have not had my January one either. Could hydroxycut be effecting this? I took 3 pregnancy tests. One around December 15th and two more in January and they all came back negative. I'm also taking the "it works" greens every morning. I don't have any symptoms of pregnancy. Just a cramping feeling here and there and the usual amount of discharge.