why arent my tests darker then yesterday

I have been taking tests since 4/23. yesterday on 4/25 I went to dr to confirm via blood quant level was at 6. took a test last night in the pm and it was the brightest I've had yet. took one this morning and it seems not as dark as last night's . I also had weird stringy cm that looked like it was brown tinged. I'm nervous to think I'm having a chemical . anyone have any insight ? I've never had a chemical I've had miscarriage after 6 weeks I'll post my pictures

this is the progression lines

middle test here is from around 9 pm last night on a four hour hold.

this is last night's and this morning's together

update!!!! I had a chemical