Mama, I understand this is scary, pero please see your OB again soon or go to the emergency room if the spotting gets heavier or you have severe cramping, these things need proper monitoring in person. Even though your doctor said it can be normal at this stage, any spotting + worry about the heartbeat really needs another check-up to be sure everything is okay. A few of us mums have been through similar scares, at kailangan talaga ng follow-up ultrasound para ma-confirm. Praying for you, sis, pero huwag mag-antay, punta na sa doctor agad.