my period was november 5th 2012 i ovulated some time between the 15th and 18th. i had unprotected sex on the 15th and the 17th. i'm due to have my period on december 1st. but for the past 3 days i have been feeling so nausious. i want to throw up. my period isn't due yet so i know if i take a test it will come out negative. i don't want to be disapointed by seeing a BFN!!! could i be pregnant?