I've had the Nexplanon implant for two years now and have only had one period in that time, which was right near the beginning. I have now just had another period, which lasted 7 days and was a full blown, cramps and all one. It has been exactly one week since I came off my period and now I have started again! Is this common with the implant as I know it can mess up your period but as I haven't had a period in two years and now I've had two in two weeks I'm worried it might not be effective or my periods are going to become far more regular and heavy.