Slow growing - 6 weeks

Just came back from a follow up ultrasound. 10 days ago I went in for my first ultrasound and baby was measuring 4 days behind, no heartbeat detected yet (they said I was 6w 1d). Went back for my follow up today and a heartbeat was found (133bpm) but the baby hasn’t grown very much since last time. The tech wasn’t specific but said 6 weeks a few days was her estimate... I’ll get an official analysis on Thursday. I am so heartbroken. We had a late miscarriage in April at 19 weeks, and I am just beside myself with worry that this baby won’t make it. A few days of growth over 10 days is a bad sign right? I just have a bad feeling about all of this.

Any words of encouragement would mean the world to me right now.