Me And My Ex Had Sex Last Month The Day

Me and my ex had sex last month the day before my ovulation day on accident. I've been eating more or starving as soon as I wake and tired all the time everyday, I was hungry at work and didn't eat till it was time for lunch and had to use the bathroom I had bled lightly and my back was hurting today my period isn't until three weeks from now. What is it? My sister had a period till her fifth month of pregnancy and my mom did in her third time of being pregnant