at 12 weeks pregnant i went for a combined NT screening to see my chances of my baby having downs syndrome. The nuchal translucency measurement was 3.6mm, with that alone my chance was 1:30 for downs. When combined with my age which is only 18, and my blood tests which were fine my risk dropped 1:1020. I had a scan at 14 weeks, everything was fine and the routine 20 week scan, everyrhing also fine. Im just so worried! What do you think?? Thanks