Pregnancy after miscarriage

Hiya,

So at the beginning of October this year, me and my partner found out we was pregnant again. (Had a few miscarriages months before) and I miscarried again on the 13th of October, due to heavy bleeding/cramps and severe backache and hip pains.

We found out we was pregnant again on the 19th of November 2020. I haven't had a period yet as they are so irregular and I have been experiencing some pains similar to my miscarriages but they don't last as long as a miscarriage, like the cramps but they are still strong.

When we took a digital pregnancy test last month it displayed 2-3 weeks but then the hospital said it was 5 weeks nearly 6 weeks of the duration of the pregnancy as my HCG levels was 321.

I'm now pregnant again and its displaying the same weeks. Do you go off by the weeks plus conception or just weeks?

Also has anyone experienced strong cramps (when it says it should be mild) that stops you form moving without any bleeding. I'm really concerned having to wait for a week to speak to a doctor and I just want to know if I should be worried about this again. As its the same pain as a miscarriage but just doesnt last as long as it did previous times.