Stopped BC last month, could i be prego?

Okay-I am not too sure if I am prego or not. I am on average a 26-28 day cycle for my period. Last month I stopped using the nuvaring. I am not too sure when my last real period was last month because I was spotting so much-that I never knew what day I started. I took the ring out November 30 and just figured that I had my period the day after. I spotted a lil on December 26th, but only enough where I could see it when I wiped. It went away after that. I havent bled at all after that. I figured that that was probably implantation bleeding, but not sure. My CM is creamy white, I feel nauseated, my back hurts, my breasts hurt,and I feel run down and tired. I took a test on December 27th (which was -), but I figured it might be too early to tell. Has anyone ever used Nuvaring, stopped and missed a period the next month and wasn't prego? My husband and I have been TTC all month long and have been having unprotected sex quite a bit.