Confused😔

Litesha
Well im 21 and ive been TTC for atleast 8 months now. I'm due on my period tomorrow, I've been doing pregnancy test all week and the second line is slowly starting to get darker, but for the past few days it has stayed the same colour. I'm confused because I don't know what to do, is it meant to stay slightly faint or will it be after my period due date will it start getting darker? Eugh, I'm so confused!!