Potential chemical ?

I had IUI on Oct 7 and am on progesterone support. At 15dpiui, I had a vvfl so my gynae ordered beta HCG which came out only 12.5. She said it is mostly chemical and asked me to repeat hpt after 4 days. I did hpt today (2 days later), the lines are darker. Initial line was barely there, visible after full 5 minutes. Today’s line easily visible and came right up.

I am confusdd what is happening. Can such low HCG translate to a successful pregnancy?

Any insights?

Updates:

Beta - 23/10 - 12.55

27/10 - 78

1/11 - 514

5/11 - 2099

It is doubling at the perfect rate but still feel it is low.