Check an ovulation calendar, i have one n mine was dead on. I checked for u n it says from the 9th thru the 15 n ur most fertile day is the 12th. U can google ovulation calendar n it will tell u when u should be. I have ovarian cyst n im 16 weeks now. Good luck
Also depends on ur length of cycle days n how long ur menstruation days are.
@scorp77 - which ovulation calendar do you use??