Brown discharge

Hi! So I’ve been releasing brown discharge since February 4. I must mention I have been on the nexplanon birth control and December 2020 will be my full 3 years so i can either get it replaced or taken out. My periods stopped 4 months after insertion of my nexplanon in 2018. I had a period once last year around this time/March so I was expecting atleast one this year. However, my periods normally lasts 7 days and is my typical period. I pms. I actually bleed. etc. But this time I’ve been having only this brown discharge and for more time than usual. I’m wondering if I should be concerned, or if i’m just releasing old blood? Also, if it doesn’t stop, what recommendations do you have to stop it? I’ve heard that I can ask my doctor for bc pills to help slow my period down but i’m not sure how true it is. Let me know any suggestions.