Line not getting darker...

So I got my bfp about 4 days ago the day of my missed period. I had a bunch faint positives on FRERs and I went to get my blood checked and I had really low HCG. Doctor is thinking I ovulated late and it's really really early in the pregnancy.

Is it normal that my tests aren't getting any darker over the past 4 days?? They look basically the same. Has anyone had faint lines that didn't get darker or low HCG level and gone on to have. Healthy pregnancy?

Starting to get really worried.

Any input would be appreciated. Thanks 💖