Personally I am a huge fan of the fetal dopplers.
Me too, we found DS's heartbeat from about 12 weeks, I could always find it by being almost fully laying down (I do remember being surprised how low I had to place it though LOL
I still have my doppler, although a friend currently has it (but isn't using it now as she's had her bub) - I am happy to chase it up and loan it to you babe if you would like to use it I totally understand your fears - although we never m/c - DS was an IVF miracle so the pregnancy always seemed to good to be true, once I started to feel DS kick though (about 19 weeks from memory) I stopped using the doppler and my worries massively decreased

Naomi