16 weeks pregnant

I haven’t had an ultrasound at all this pregnancy so idk what’s going on in there . I’ve been listening to my baby heart beat with the Doppler . So tonight I’m feeling around for the baby I heard the heartbeat on the left side it was like 154 and I heard another one on the right side it was in the 140-150 . Could I just be picking up the baby heart beat on the other side ? Ain’t no way in hell I could be having twins OMG 😥