Should I be worried about light brown discharge?

AF is 3 days late and I have had vvfl getting a little darker each time on hcg tests for the past 3 days. However, I have also had very light brown discharge for the last three days as well. It's only on toilet paper when I wipe-- doesn't even make it to a panty liner. But I'm worried that it's lasting this long. I miscarried in December and am feeling pretty scared about it turning into blood. Anyone else have this and still end up having a healthy pregnancy?