I was stupid :/

I had my little girl 8 weeks ago and I got on birth control a week and a half ago the day I took my second pill my s/o and I had sex it was spontaneous and unexpected so we didn't use a condom but he pulled out I don't want to become pregnant again and it was so so stupid of me to allow it but I was so caught up in the moment..what are my chances of not becoming pregnant *if it helps I exclusively breastfed and I read that for the most part stop ovulation breastfeeding the first 3 months and I've been taking my birth control everyday same time*