doppler at er no heart beat

Monica.
Hey I am not too worried but According to LMP Im 12 weeks today and DOC im 11 weeks 2 days but i went to the er yesterday because some
Jerk rearended me and left the scene The car was dented a little and my back was sore so I just wanted to check the baby. the np could not find the heart beat then they order an ultrasound but had to wait for result of my pregnancy test when Im clearly pregnant frustrated I just left but should I be concerned they couldnt find a heartbeat with a doppler?