Slow rise after 6,000?

My first blood test was the 17th, my Hcg was at 96. My second blood test was this last Monday, and it was 9,813 with my progesterone being 16.45. I did another blood test yesterday and it came back 13,813. Only 4,000 more in 48 hours, not doubled.

They are unsure about how far along I am, until Monday when they do an ultra sound. But what do you guys think?

Is it bad it didn’t double ? Or is that a good enough rise in 48 hours? My last period was February 5th, but she doesn’t believe I am that far along especially with my first Hcg test and when she felt inside , she said I wasnt swollen like I’d be at 7 weeks

Thank you!