My line is not getting darker???

My line is not getting darker?? I got my BFP on Tuesday and the line on the internet cheapie isn't getting any darker :( I'm 4 weeks 4 days. This picture is from yesterday morning. My period is 5 days late today. I haven't taken one today. Should I just stop peeing on sticks? I'm obsessing over the lines and it's stressing me out....