6w ultrasound and hcg levels

Lindsey • Mother of 4 boys, #5 due feb 11th, midwifery student, avid reader, adventurer.
At 4w5d my hcg level was 6026. Went back in yesterday at 6w0d and my hcg level was 41,000! They swear only 1 baby. I could see his/her heart beating :)