I started feeling flutters at around 19 weeks (but not massively recognisable - they could still have been mistaken for wind if I didn't know better). Started to feel much more regular and stronger movements from around 21 weeks and am now regularly wincing at the ferocity of them at 24 weeks. I definitely felt things earlier with dc1 though.
Try not to panic, it could just be that the baby is facing a different way or your placenta is in the way or something. I've had 2 mc's as well and know how worrying it is - especially when you're approaching your 20 week scan.