so first ultrasound i had was at 6w4d and they saw heartbeat gave me a due date..told me i wouldnt get another ultrasound til 21 weeks.i know ultrasounds dont need to be done every couple weeks BUT i’ve had 4 previous miscarriages and i feel like waiting that long in between is kinda strange and absolutely nerve wrecking for me.. does this sound like a long time to wait to anyone else?