Possible miscarriage again

I had an ultrasound and they expected 7 weeks 4 days but it measured 5 weeks 4 days. So it was to early to detect a heartbeat. I had blood work today and I'll go in 2 days for more. Than on Monday I'll get results to see if my hcg levels are rising. I had a miscarriage over the summer. I'm so worried it will happen again. Did anyone else scan 2 weeks younger than they thought and had a healthy pregnancy?