BFP, but slow rising HCG

Hi everyone,

Got my BFP on 8/28 after AF didn’t show. Was off course thrilled, but after a miscarriage in 4/2018 and an ectopic in 2/2020, naturally I’m so hesitant. Unfair but that’s reality after you experience a loss let alone two.

Went for an ultrasound on 8/31 and they said I’m 4w5d but no sac could be seen. They said it still could be be too early so I have another appointment on 9/9.

I’ve since had bloodwork three times testing my HCG and below are my results; not doubling the every 48-72 hours as they suggest should happen and im scared to death I’m losing this baby too 🥺 anyone else had slow bc rising levels like this and still had a successful pregnancy?

8/31 390

9/2 519

9/4 574