I Have The Nexplanon Birth Control In My Arm, And

I have the nexplanon birth control in my arm, and I have had it for a little over a year now, my periods have always been irregular, I had a menstrual cycle a week ago, and ever since I have had a muddy brown discharge which I know could be considered old blood, but I have had complete cycles of old blood periods. But this is a different kind of brown, one that I have never had before and not to mention, I have a constant cramping sensation as if I'm on a period, but I ended my actual period about a week ago, stopped bleeding then a few days later this brown discharge has been constant.. I have not had sexual intercourse for atleast 4 months, so I know I'm not pregnant. I have loss of apetite, having trouble losing weight, fatigued, and now my urine is cloudy light yellow. Should I be concerned?