Long black oval shape above sac 6w ultrasound!

I just had an ultrasound down, I'm 6w6d. Baby is measuring good and there is a heartbeat. But above the sac , or it looked like it was above anyway, there was a long black skinny oval shaped spot. Has anyone had something like this on an ultrasound? What was it? Any advice or anything ? I just had a mc before this so I'm scared. I asked the ultrasound tech what it was and of course she couldn't tell me she said I have to wait for doc to tell me. Any advice or any ideas would help!!