What Causes White Vaginal Discharge Post Unprotected Sex?

hello I m priya 23years old, I had a sexual intercourse with my bf on 28th feb without precaution, so I use ipill after, n after 10 days, I had ma periods, till den, my vagina is regular ly discharging white fluid in much amount. .wt should I do.? Is dis problem occur only after having sex, or is it normal, shoul I tell my mom