If you have sex a day after conception date does that mean you where already pregnant?

Hmmm.... yes.: Conception is the start of a new life, a new baby. That means 1 second after conception, you have been in gestation for 1 second and the new baby embryo is 1 second old. Do realize that at that very moment, you are about 2 weeks pregnant because pregnancy weeks are officially counted from the beginning of the last menstrual period, or 2 weeks before ovulation.