What Causes Abdominal Cramps And Irregular Vaginal Bleeding After Having Unsafe Sex?

Hello, I had unprotected sex the week of ovulation, 8/4-8/15. That whole week, week after, and the week of my expected cycle, I have been experiencing heavy cramping. My cycle started 8/19 as expected, however it was pinkish. The second and third day I had heavy bleeding with heavy cramping. The fourth day, light bleeding and fifth day no bleeding at all. The six day I had unprotected sex, while experiencing mild, light cramping. The seventh day, I was experiencing mild, light cramping with pinkish spotting. My cycles run every 26-28 days the last several months and my cycles have last about 7-8 days the past three to four months. This month only 4-5 days..I have been off the depo and birth control for about 2 years now..what am I experiencing? Also I haven t went for my yearly pap check up. What should I do and expect out of these experiences? Thank you.