Line won’t get darker!

Hi,

I’m trying to not panic but I’ve gotten a faint positive everyday since Tuesday on multiple brand tests, but they won’t get darker 😭 they are faint but there. I thought they would be darker by now but they aren’t. The first test was in the afternoon and I’ve tested every morning with FMU and they’ve all looked the same. My expected period is Sunday. Should I be worried I had a chemical? Or is it normal for HCG to go up slowly in some others? I have no bleeding or spotting, and I have very minimal twinges in my stomach as well as nausea. Anything will help, thanks.

Tuesday afternoon on the left and Wednesday morning on the right:

Wednesday afternoon:

Thursday AM:

Thursday afternoon:

This morning: