What Causes Pinkish Discharge After An Unprotected Sex?

hi i am 23 , 5 ft 4 and 2 days ago i had finished my birth control pills (mircogyon) but that night my boyfriend and i had unprotected sex and he didnt pull out. but today i noticed wheni went for the toilet, that i had pinkish discharge??? although i due my peroid in few days , does this mean that my peroid is on its way??