Are your twins measuring small? Is this normal?

At 8 weeks, my ultrasound showed I’m pregnant with twins. But no heartbeats. And the babies are measuring small, only 5 weeks.

Has anyone else had twins measuring several weeks behind - is measuring small early on normal for twins?

Im desperately praying the babies are okay and that we pick up a heartbeat at our next ultrasound. Eager to hear from anyone else with experience with small twins or no heartbeats/blighted ovum. Please no discouraging comments at this time; I already know it’s not looking good.