Help needed!! Confused by conception and due dates

Hello ladies i need you help.. I’m currently 11 weeks and 2 days pregnant, I just found out my due date just the other day as well as my conception date, however I’m abit confused on why it said I conceived on the 7th November when I’m pretty certain I slept with my partner a few days later. I have no idea when my last period was so that’s no help either, many people have said the accuracy could be wrong and many people have said early ultrasounds can be  within 3-5 days of accuracy, here’s my question! Does that mean 3-5 days within accuracy after I "conceived" or before? Many thanks x