Gestational sac sizes

I had a scan last week and my gestational sac measured 5mm but nothing was seen inside. They didn't tell me how far along they thought i was, just booked me in for another scan.

Longest week of my life and the scan today showed 7mm but still no yolk sac or fetal pole.

So im still unsure whether this is a viable pregnancy or not. My periods are irregular (sometimes 25 days sometimes 32).

My last period start was 24th june.

Has anyone experienced similiar? I have already had 2 miscarriages so very worried.

Please let me know your stories good and bad xx