99 BPM too slow??

Kelsey
Hello! I am 7 weeks today! I did go in for my first US and after a little scare, they were able to find our little bean! They thought I was about 9 weeks but I ended up measuring about 6 weeks 4 days! The heart beat was 99BPM. After seeing other post, I feel 99 BPM is low -- can anyone ease my mind a bit!! Thanks!