What you have experienced is extraordianarily distressing, however detecting a heart beat via doppler is extraordinarily difficult at 10weeks. The baby hasn't risen up over the pubic bone yet and this makes it near impossible to hear. Sometimes it can be difficult even at 14 weeks. This is also due to the fact that your baby is so tiny and can (and often does) move away from the doppler.
I wish you a good result from your scan which I am sure you will get.
Love and baby blessings,
Deb