One twin smaller than the other

A HAYES

Ive never been pregnant with twins before so this is all new to me. At 6 weeks I had an early scan due to bleeding. At the scan there was one healthy baby and a second empty gestational sac. 2 weeks later i had another scan and there was a second baby in the sac. At 9 weeks i have di-di twins. The second baby is measuring 8 days behind the other, has lower amniotic fluid and has an abnormally shaped yolk sac. I have another scan next week (12wks) and am terrified that the smaller baby will no longer be developing. I feel like my doctors have put it in my head that thats what will happen and now im worried. Has anyone had ANYTHING like this with twins and both were born healthy? Im just looking for some reassurance i guess.