Tests don’t seem to be getting darker

Hi everyone I need a bit of advice please, my tests don’t seem to be getting any darker and I’m worried sick 😩 I’ve had a tiny bit of cramping the other day but nothing major, I’m not spotting or bleeding or anything. I’ve done tests with FMU and they still don’t seem to be getting any darker. I’ve had a miscarriage before and I had a lot of cramping then leading up to it and during. Any advice please? We can’t get blood work here in the uk either