I Have The Birth Control Implant In My Arm And

I have the birth control implant in my arm and i've had it for almost 2 years now. I stopped having my period for about 6-8 months but for the past 2 months my period has come back. I have almost constant spotting now and even though i was on my period 2 weeks ago I am on it again. what's going on? what should i do?