Salam! Sayang, ini perkara yang perlu tanya doctor je, especially about heartbeat at 6 weeks, setiap pregnancy berbeza dan timing dia important. Jangan risau dulu, tapi please make an appointment dengan your OB/GYN as soon as possible so dia boleh explain properly and do proper assessment, okay? Doctor akan dapat tengok better with the right scan. Hang in there, mama, first pregnancy memang macam-macam perasaan, but your doctor is the best person to guide you through this.