Birth control period question

So after having my son (he’s 2 1/2 now) my periods were VERY heavy. The GYNO suggested birth control to help. It’s definitely helped. I’ve been on the birth control for at least 7 months if not

Longer. I have the kind that I take 3 rows and then nothing for the week of my period. Always start and end during the week I take no pills. I started my new pack this past Sunday the 19th and period had ended. So I’m almost a week into my first row of pills and a few days ago I noticed I’m spotting brown. I know that can be normal to have brown discharge after period but it’s been almost 6 days? No other symptoms. Just when I wipe there is brown like old blood. Anyone ever experienced this?