Started pill

Hey iv been on loads of pills previously and had bad reactions, but I went off them for 2 years to give my body a break. I recently went on yasmin as I found it to be the best pill. 
​Iv done research and it says allow a month before allowing your partner to ejaculate inside you, however it also says online and on the pack allow 7 days for it to become effective, on the 8th day taking it my partner ejaculated inside me?
​Am I protected or have I completely read it wrong?