What Causes Menstrual Cramping And Delayed Period After Having Protected Sex?

Hello, I have been sexually active with my partner for about 3 months now. We have used protection each time but I don t know if we had a mishap or not. I m now 4 days late for my menstrual cycle and it is usually on time every single month. The past 2 days I have been cramping, and being hit with a nauseous feeling and also I ve feeling wet like my menstrual is starting but when I check, it s milky white discharge. I m baffled and trying to wait it out but I m very nervous.