So I've had an early scan and I've been dated 6 weeks 4 days from my measurements. People keep telling me that it's 2 weeks before that you are pregnant... So that would make me 4 weeks?? But why would my baby measure 6mm+ I'm only really worried due to having sex on around 25th/26th dec 2014 with my ex who is my sons dad, we have been through a really tough yeah and to someone else I was seeing on 17th jan. But if I'm 6 weeks 4 days I'm guessing it would mean I got pregnant on 25th/26th? Please can I have advice without the negatives! Thank you! X