Fetal Doppler

Megan • Mama to our little rainbow-Finley James
So I have a fetal doppler I purchased online and haven't been able to find the heartbeat yet!  I'm 9w4d today and we saw the heartbeat at our 6 and 8 week ultrasound appointments so I know it's there!  Anybody else have a doppler and have better luck? I'd love some tips!