Line progression

So im a little confused on how i check my line progression as the test ive done just now is BFP but if i compare it to 2 days ago the line is so pale compared as the old one has since gone so dark. I cant compare the two as its out if the time frame? Do yall just go by photos of the tests in the time frame to check line progression as im freaking out? Mine is clearly lighter than the one 2 days ago out of.time frame? Do you get what i mean? Sorry to sound confusing.