why?!

Please give me some insight ladies. I’ve been on birth control for almost 2 years (lo lo estrin fe) my period is fairly light and lasts 4 days. Sometimes I spot in the middle of my pack. And sometimes I don’t. But this time i wiped and it looked like it had a tint to it like brownish, but Deff didn’t look like blood. Is this normal?! I’ve called my doc about spotting and she said it’s normal but of course I overthink everything lol. Thanks:)))))