Is this a possible chemical pregnancy? No line progression

So I started testing 9dpo which I got a vvvfl on

the first response early detection test. I also

tested my hg which was a 6. 24 hrs later I

checked it (10dpo) and it was 15. I am still in that

gray area 5-25 for hcg. It is progressing however

the lines on the pregnancy tests aren't. They are

the same very faint as they were 2 days ago at

9 dpo (today I am 11dpo). Here are a few pics.

Am I possibly having a chemical? Usually w my

other kids I had clear lines by this early but I know

every pregnancy is different: