Nexplanon (the bar) is messing with my cycle

So I recently got the bar in November when I was on my period and things were fine until it was time for my next period to come. A week before my schedule period date I started to notice brownish-red  discharge which turned into brown spotting then brown blood during the whole week  now I'm starting to get red regular blood mixed with some brown blood still and I am going on day 8 now... I know some of this is normal and to be expected but is this supposed to go on for this long? Please help me any info would be great.