Hi, welcome to healthcare magic.
It seems to be too late to answer your question but I would like to make clear two points:
First: the answer to your question is that your due date is in the first few days of may not in April because in your case ultrasound
is more reliable than your dates.
Second: concerning the two vessel cord: an experienced pediatrician
shoul attend delivery of your baby and be notified by the two vessel cord. Your baby should have a fetal echo done after delivery to exclude cardiac anomalies.
Wish you good luck.
Dr. Ahmed Bahaa.