My period for the month of April was from ApriI 6-9. I had unprotected sex on April 16 so I used Nordette as an ECP and had a 3-day withdrawal bleeding from April 25 until 27.
And then, just 18 days later, on May 13-15, I had a moderate bleed which I assumed was my period for the month of May. Now I'm confused as to how I could determine the arrival of my next period. Should I count from the day of the withdrawal bleeding, or the bleeding that occured 18 days after?