You are most fertile 10-14 days before you start your period. For a women with regular cycles you can estimate when ovulation occurs. In your case it appears that you are ovulating at the beginning of each month.
Based on the timing of when you got the latest bleeding it sounds like this was your period and it was a little different from usual. Sometime to point out here is that if you notice you bleed after having sex in the future, you need to be checked out by a doctor because that could signal an STD.
Since women can get pregnant any time during her cycle (may ovulate an an unexpected time) you should take a pregnancy test 2 weeks after unprotected sex.
One day periods are not too concerning, especially if you are on birth control. I would keep an eye on things from here on out -- if it seems abnormal next month as well, I would call your gynecologist.
two weeks after period and two weeks before is the most fertile time in your cycle..
Not exactly- women are most fertile about 2 weeks before their period, not after their period unless they have a typical 28 day cycle.