Fertility

Weird question and I’m definitely ignorant to this and should do better. But my boyfriend and I had unprotected sex last night and this morning and he did not pull out and came inside of me. So, I looked at my calendar and realized my fertility window started yesterday. I’m just wondering if anyone has any stories on getting pregnant after having unprotected sex early in their fertility window. Or any info on chances of being pregnant. Of course this would not be planned but I would not be upset lol.