Help!!

Went for an ultrasound on 1/29 and measured at 5W. Doctor wanted to see me again a week later for another ultrasound. I went in today while the sac doubled in size, there was no heartbeat or “baby”. I’m so scared and losing hope. She said it’s just really early but the fact that the sac is growing it’s doing what she’s expecting and not to worry. Has this happened to anyone? Next appt is at the 8 week mark. She said she’ll me earlier if I wanted. I feel like I’m going to lose my mind and can’t stop tearing up. Due date is 9/30. 😰