Ductus Venosus not found?

So we had our 12 week ultrasound and they couldn’t find the ductus venosus. They said everything was probably fine and that it isn’t a big deal. My partner also said the same thing and he’s a Doctor so I should probably trust him but I have this feeling of dread. Has anybody had the same thing and they found it or not found it? I see my general practitioner in about 2.5 hours and she’s going to discuss the report with me as I’m a high-risk pregnancy. I’m just really concerned that it’s not there.

Everything else is perfectly functioning like the heart, aorta all those things which would lead me to believe it just hasn’t been spotted over not being there. This is such a rant and I realise I’m probably rambling but I am afraid especially after I just read a number of medical journals about fetal mortality due to this. I now have to have follow-up ultrasounds at 16 weeks and at 20.