Longer lasting period?!

I have been on BC for over a year, I usually have two days over brown discharge then my period or withdrawal bleed lasts for 5. This time I had some discharge but very little. The withdrawal bleed was normal, slowed on day 5. On day 6 I started to have red blood again and now it’s day 8 and I’m still having brown discharge. I haven’t done anything different other than just turning 21 and I have had some drinks recently, nothing crazy but some. Help