Doppler!....twins??

Hi ladies, im currently 12 weeks pregnant with baby no.6 because of previous miscarriages i decided to buy a Doppler to see if i could listen to the heartbeat...for a bit of reassurance. I read that you are not supposed to hear the heartbeat till around about 14 weeks, i received the doppler at 10 weeks and found it straight away and quite strong. The past few times iv used it me and the hubby are pretty sure we can hear 2 heartbeats! But tonight there was a really strong heartbeat at one side of me stomach and a really strong one at the other side! Could it just be the same heartbeat? Maybe an echo or can you hear it from both sides?