high chance or low chance?

My boyfriend and I have been doing the pull out method for almost the entire time we have been together. If we had gotten pregnant, we would have been thrilled, but we haven't been actually trying. We are both adults with jobs and a place to live, we have been together over a year and we are 100% in love and happy together. I started birth control recently, and within the first week and a half of being on it, my boyfriend came inside me. Since it was my first pack, but I did take it on time every night, do you think the chance is low or high? It was during my "ovulation" time, but birth control is supposed to stop ovulation? I've had the lightest pink mixed into my clear, watery discharge today and I'm officially in the two week period before my period.