Spotting first trimester

Sy at 6w ada spotting colour brown.. Pegi scan takde sac, but check upt still +ve.. Ada 2 possibilities, either salah tarikh weeks means dia still small tak nampak sac or it could be ectopic.. So far sy takde cramps kadang2 sakit belakang sbb over standing/jalan je.. My next appointment will be another 2weeks to check but in the meantime kena monitor the spotting (now its been 3days)