Prolonged period????

Ladies! I'm on the implanon bar for the past 2 years and it does make my period longer say it could last for 12 days.. I had my period for 8 days and I had a 3 day break of no bleeding and i started to have very dark spotting which led into me bleeding for 2 weeks ( I'm still currently bleeding) would anyone be able to help me? I don't know what's going on!