MY PERIOD WONT END

so I got the implant rod on Jan 26 and my first period after that was on the. 10th of February. On my birthday what a great present. My periods have always lasted 5 days but so far it's been 7 days and the flow doesn't seem like it's getting any lighter. It's like medium and when I take my tampin out the booodbis like dark brown most of it. Could the implant be giving this affect?