Okay I don't know what's working with me I was on birth control the patch I use it like they say to do so 3 weeks on it and the 4th week off then I didn't use it after that me and my fiancé had intercourse after my period was gone and that was on December 22 We been trying to get pregnant I would of thought that could of happen but I took a pregnancy test on the 31 of December and it was negative then I got my period January 13  and just got offf it so what can be wrong with me..