Help babys heart rate

Hey guys, I went to the doctors today, im measuring 6 weeks and 3 days but baby heart beat was measuring between 97 and 104. My doctor said he is concerned because the heartbeat should be at 110. He said im close to it but its still worrying him. I go back on Thursday the 21st to see if its normal and has gone up. Has anyone else had issues like this or know anything about it. Im a little confused cause my husband looked it up and it said from 6 to 7 weeks the normal range is 90 to 110? I'll be devastated if something happens i just lost my son at almost 17 weeks in oct.