If your period are regular and your next one is due on the 14th, today would likely be your ovulation day, so feeling nausea right now might be too early to be considered a pregnancy
I am not sure what is causing the spotting. If you were not on the pill
, I'd say you just ovulated (some women experience spotting during ovulation). That said, some birth control pills are known to cause spotting mid-cycle. Which BC are you on? Have you missed any pills?