beats per minute

so when I was 6 weeks and 5 days my baby's heart rate was 138 beats per minute and when I went to an appointment yesterday at 9 weeks and 1 day the baby's rate went way up to 179 beats per minute and they were moving around a lot the doctor says depending on what they are doing it will increase or decrease the heart rate just like ours... any one else experience this? baby's heart going from a low to a high? And I swear I seen two babies because she as she was moving to the other side i thought I seen another baby but I'm sure the tech would of told me lol.