Can’t find baby heartbeat

I’m 15 weeks today, I heard baby’s heartbeat at the doctor last week it was hard to find but very consistent and was further down. Today I got my own in the mail and I tried and tried and can’t find the heartbeat anywhere. I went further down where the lady found it and everywhere else and still couldn’t find it. The first time I tried for 10mins the second time for 20mins and gave up 🥺 thought it was gonna stop my worries and made it worst