High risk on calendar???

Tracy
Why does my risk keep going up? Had sex the morning my "fertile" window opened i was at a low percentage, that was Saturday we haven't done anything since but my rate went from like 3% to 14%, I don't understand why? We use withdraw method...I assumed the % would stay the same or go down if we weren't having sex. I'm new to glow, I'm a little confused on how this works...