My chances of being pregnant

I have been using this fertility calendar for quite some time now to avoid unwanted pregnancies; So far, so good. The problem now however is that I didn't check my calendar for fertility before being sexually intimate with my b/f this last time. I checked it the next morning, to find out that we had unprotected sex (and he came inside of me) the day before ovulation. What now, are the odds that I am pregnant?