I went through something similar, mummy, and the waiting for the next scan was honestly the hardest part 😢❤️
In my case, baby was measuring behind at the early scans, but a week later there was good progress and the heartbeat had picked up. At this stage, even a few days can make a big difference. For now, I'd hold on to the fact that a heartbeat was seen and try to take it one day at a time. Wishing you the best for your next scan 🤍