I had sex and it felt like that sperm went inside, but I had my periods on right time, which means that I had sex on 8th and on 15th I had periods, in 3rd day of period a tissue came out from vagina and had a much more flow than what I had 2 days before, it was a 5-6 days period, but on december, 13th was my date, and I am not having period till now, why is it delaying. What was that tissue? I felt like it was a zygote or something like that, why is it delaying? When will I be having my periods.