What Causes White Vaginal Discharge?

i have been having unprotected sex and my temperature has been 98 and above since i obvulated last my period was suppose to be present this week but i have missed an period and day 3 of my missed period my temperatue dropped to 79.1 is that normal since i have been trying to concieve.I gt an browinsh discharge 2 day before i was suppose to start and day 3 i have been having white discharge