Doppler confusion

This is my second pregnant and I still have my Doppler laying around from the 1st. I’m just over 8 weeks and I know it’s almost impossible to find baby but I decided to try. I know exactly where to look and bam- within minutes I find baby nice and low to the right with a heart beat around 140. My confusion is that if I go over to the left side I’m picking up the heart beat clearly but this is around 127-130. Can it just an echo from the baby or is it possible I’m detecting twins? I have not had an ultrasound or even a doctors appointment yet. They aren’t seeing me until 10 weeks this time.