6 days late, past sugar pill, now this?

Hey girls, so I am 6 days late. I’m on the pill, yes I have sex. Saturday I noticed super light brown discharge when I wipe. Sunday was the same with a light pink spotting, and then this today only one time. I took a test Sunday morning and it was so faint that I was told to test again. I took another test but it was invalid. I plan on calling my OB/GYN tomorrow to get something figured out, but opinions do help.