Spotting? (No pictures)

I've been spotting off and on every couple days since 5w3d (I'll be 7 weeks tomorrow). It's always a small amount and it's always a medium-light brown color. It's never been pink or red and like I said it comes and goes. I wear a panty liners but it never fills. I have an appointment tomorrow morning, it's the earliest my doctor's office could get me in. I talked to a nurse who told me I shouldn't worry unless it got heavy or red, neither of which has happened. Has anyone experienced this before? I'd love a little input! I know I'll find out what's going on tomorrow but I'm dying just waiting.