Hi, Thanks for using HCM.. i understand your concern. Was your periods regular? Usually period of pregnancy is calculated from the last menstrual period and preg test become positive by 4 weeks.. But in your case preg test at 4 week came out to be neg.. So it would be better to get a scan now to know the period of gestation. Usually Gestational sac appear by 5 weeks and fetal pole and cardiac activity by 6 weeks and followed by that by CRL Gestational age can be calculated. I think u have got a delayed conception. Since u also have brownish discharge its better to get scan at the earliest to see for any subchorionic hemorrhage.. Hope i have answered ur queries.. Good Day.