Low heart beat

Hey ladies again! I have one of those heart stick looking thinking that's your OBGYN would use just to check the baby's heart beat instead of a sonogram... I had a D&E Jan 12 2015 and we've been trying ever since.. I checked tonight with that little machine ( it looks like a microphone) if the baby is THAT new is it possible the heart rate is only 92 because I could swear that it's a heart beat.  The first time I was pregnant it didn't show up in my urine until I was 3 months.. So I actually found out at 4 months and 6 days that I was actually pregnant for a routine trip to the gyno .  Could it be an early heartbeat?