Single Umbilical Artery

I am currently 30 weeks pregnant and my doc told me last week I have a single umbilical artery. Prior to this she told me I missed the time to have testing for spina bifida markers. I really hate this doc. She has never once done an US herself, i am 99% sure she doesnt know how to read one. My problem is I cant get a repeat Ultras for 3 more weeks. If the baby did have SB, it would be past the time they could do anything about it. All i do is cry and i just cant go on. My doc office acts like Im crazy and will not even refer me to a different MFM doc sooner bc they say I dont need a referral bc i have a PPO. BUT i told them, the MFM docs i contact all say they are only taking referals d/t Covid. Im just worried sick and feel so hopeless. Its a holiday so they would keep me out of labor and delivery at the hospital if i i aaed for a 20 week US.