What Causes White Viscous Discharge With Lower Back Pain?

I had sex December 15, 2010.My period was late that month.It usually comes on twice a month.It came on once that month and so on.I had my period the first week of this month.Since my period I have noticed this whitish gooey ooey stuff coming out of my vagina.I have been having headaches everyday,my lower back continues to hurt,and my breasts are really sore.What could this be?