help.. question

I'm having twin boys. I'm 13w&6 days. I feel like I shouldn't trust my doctor... she told me one of my babies are stuck tangled in the umbilical cord. but I thought that they couldn't find out that until the baby was born. I'm so super scared right about now. She told me to lay on my side so baby A can move around some more. I'm confused someone PLEASE help me 😭😭