help me

TAE

Can someone explain to me how implantation works ? I took a pill on my 3rd day after ovulation and i was at a 3% chance of pregnancy.. my period came late yesterday normally it’ll come in the morning. But since it’s been on it’s been kinda heavy. NO CRAMPING which is unusual.. and very light tissue shedding.. my first pregnancy i was on depo and found out at 5 months that i was pregnant. Has anyone gone through this but still came out pregnant ?