Low HCG but perfect ultrasound

Samantha

Yesterday I had a ultrasound 6w6d looked perfect. Strong heart beat of 139. But my HCG are levels are someone who is only 4-5 weeks... what does this mean ?? I'm worried.. I'm supposed to follow up next week. Hoping this baby sticks this time 🤞🏽🤞🏽🤞🏽😫😫