Well, the way it works is that you ovulate for 24 to 48 hours and that's it. BUT, sperm can live up to a week and impregnate you if there when you ovulate from sex days earlier. AND, some women will have a rare occurrence of a second egg. There is no 'safe' time to have sex. There are more likely times that a woman conceives which is usually day 9 to 20 of her cycle. Those are the days that women have sex if trying to get pregnant. Most women ovulate around day 14 to 15 on average. Day 1 is the first day of your period so you count from there. But cramping doesn't really tell anything. It could be your period coming. So, just wait until it is to show up and if it doesn't, take a test. Use protection EVERY time though from now on. good luck