Found two heartbeats different sides I know one is probably mine

So I’m 12 weeks 3 days and listening on my Doppler and I know where baby’s heart usually is so I always go to this spot as it’s where the ultrasound tech puts it and baby seems to like that spot but today I tried other side and heartbeat was there then I went to usually place and there was a heartbeat even though this is my third I can never tell difference as non of my babies heartbeats have sounded like a horse galloping or a train so bit hard spot difference