Anomaly Scan

I went for a 20 week rescan as baby boy was playing up. They managed to check everything and he is perfectly healthy and normal. But one concern they had was that his cord insertion was normal and as it should be BUT his umbilical vein was an abnormal shape. It was shaped like a question mark. And it had a white dot in it. She called another lady in and they were both unsure why it looked like that. I've been referred to a specialist so they can take a look at it. But have to wait and see. I'm just SO worried now. Anybody else had this happen or know why this could be?