Spotting at 4Weeks

Hi, sy first time mom. 4w ada spotting dark brown and dh check dri bawah, ada kantung. cuma bby too small. Doktor remind utk "dtg balik 2-3 minggu k utk check heatbeat and baby" and bg ubat kuatkn rahim. Nak tanya at weeks 6 dh boleh tahu tl heartbeat and kantung semua? sbb gusar btl hati ni hari2 check dark spot 😭