Implanon/ Nexplanon

Hey Ladies, 
Just wanted to ask around about other girls' experiences on 'the rod'?
I got mine inserted 10 months ago, and for the first 6 months it was fine (periods were timely/ light, no cramps, no problems).
But as of three months ago, my periods come and stay for about 3 weeks at a time. Not just spotting, but constant heavy bleeding. 
What is/was your menstrual cycle like on this?
I'm wondering if anyone else has experienced something similar?
Thanks for reading,