Unprotected Sex

So.. My boyfriend and I have recently been having unprotected sex for the past 2 weeks. We've done it 3 times. I was past my ovulation date.. So does that mean that pregnancy is impossible? Is it possible for people to randomly ovulate? My period is a week away and i havent felt myself all month; extremely hormonal along with major breast soreness. I cant help but be a little nervous. Any feedback would be appreciated.