Period changes/way longer due to implant?

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I recently got the Nexplanon implant. When my period was supposed to come on it was 5 days late.. now I’m on day 7 of my period being on and I’m concerned its never going to go off. Right when I see brown blood I think it’s going to end and the blood slows then a few hours later it goes back to being regular red period blood. Is this normal or should I call my doctor? Also what have your experiences been?