Do you count how far pregnant you are from your last aunt flo or from the day you did the baby dance?

They count from the first day of your last period. They do it like that because some people dont know exactly when they conceived. People who are actively trying BD pretty frequently to increase chances. Even though you know when you BD, it could have been a day or two later when conception actually happened. Be happy, you are already 7 weeks in, only 33 to go!