I'm 18 years old and suffer from congenital hypothyroidism and I am pregnant. I had protected sex on the 25/26th august nd I got with my partner on the 5th of october. On the 5th of october. We had sex on the 5th and 2weeks later find out I'm pregnant but my scans are sayin I'm 3 week further gone then I am which means I concieved on the 17th sept. Can someone help me understand please..