Sayang, I'm so sorry you're going through this uncertainty, it's really stressful, I know. Please go to your doctor or emergency department as soon as you can, especially since you had a miscarriage before and now the measurements and scan results aren't matching your expected dates. This really needs proper follow-up sooner than 3-4 weeks, don't wait that long. Your doctor needs to rule out ectopic pregnancy or other concerns, and you deserve clarity faster than that. I haven't personally been through this exact situation, but a few mum friends have had delayed scans or confusing results, and they all said the anxiety is worse than getting checked again quickly. Trust your gut on pushing for earlier review, you know your body, and you've been through trauma before. Sending you strength. Please get checked soon, okay?