I had the same thing happen!! Turned out I should have been 9 w 5 d but was only 7w1d!!
Slow heartbeat at only 64bpm but 5 days later he was at 174 bpm.
Dont by give up yet!!
I would prepare yourself for bad news, because you could lose the baby, but not give up hope yet. If there is still a heartbeat then baby is still hanging on and it's not over till it's over.
They told me my baby's HR was too low on my ultrasound and that it would most likely miscarry. I'm 27 weeks now and he has a normal HR of 140. Sometimes you ovulate a little late and the dates are wrong so don't rush into anything you're not 100% comfortable with.
R u hcg levels rising? Doubling?