PLEASE READ AN HELP IF YOU CAN 💗bleeding behind placenta..

at my 12 wk ultrasound i had blood behind my placenta my doc didnt tell me till yesterday at my 16 wk check up said not to worry most of the time it gos away so wont be checked again till my 19th wk thats 8wks of not knowing what's going on she just checked the heartbeat..im scared this is my third and didn't happen with my first 2 plus 8 months ago i had a hip an pelvis fracture ontop of a ruptured blatter an fractured rib so makes me more scared.what would u do what are your opinions please .