pregnancy right after giving birth

D
I just had my baby in November and I've been taking the "mini pill" because I'm breast feeding . Last night my so and had sex and I haven't taken my birth control since last Thursday because I had left for the weekend and forget it at my house anyways we had sex he didn't pull out and now I'm really worried I could be pregnant again I know your very fertile after a baby . Anyone other ladies get pregnant quickly after birth ?