ok so me and my partner recently had unprotected sex. I usually am on birth control pills specifically for my period due to pcos, i have been on that for about a year and a half, my period has been very regular. 4 days later i got my period. it was very light and a light brownish color. later that night i noticed my period completely stopped, its now 2 days later and still dont have a period. what does this mean?