Implant birth control

So I got my implant in August 2016 and had a good first year and a half with it but now I have been having my period for 4-5 weeks and yes I mean WEEKS! In between periods is about 1-2 weeks in between and it is driving me nuts I have gained 30-40 lbs in a year and I have a fast metabolism usually and I haven’t changed my eating habits at all, and my fiancé can’t handle the blood so we have barely been having sex when I’m on my cycle when we normally do 2-3 X per day. It’s miserable I’m about ready to cut it out of my own arm 😭 is anyone else who is or has used nexplanon experienced issues like this.