What Causes White Color Vaginal Discharge?

My period is now 5 days late and I have been having white/clear vaginal discharge instead. My boyfriend and I have had oral sex, but not vaginal sex, and we dont believe our genitals ever touched. My doctor has given me premarin cream to use on my nose to help strengthen my bood vessels due to having chronic bloody noses; I will have an appointment with a nose specialist at the end of October to more effectively treat this problem. I am also a first year college student and have been very stressed. I am just wondering if my period is late, or if the discharge is replacing my period, or if it is possible that I could be pregnant.