Positive pregnancy test but line not getting darker

Hi ladies

I know it's early days but I'm freaking out a little.

I did a test 12,13 and 16dpo. However I tested at different times and the last test i think I did incorrectly (its a midstream test but i stupidly used a urine sample pot)

Im worried as today's most recent test doesn't seem to have got darker from 3days ago.

Could this be a bad sign? Is it too early to tell? Did anyone else get fainter lines than expected in week 4

Sorry for asking silly questions... Just panicking 😔