I have the implanon in my arm, however, it expired on 2/21/2012. I have never had regular periods, and now I am showing multiple sign of pregnancy (nausea, fatigue, food aversion, enheightened sense of smell, tender and swollen breasts, headaches, increased need to urinate) and I have taken a couple of pregnancy tests over the last week, and they keep coming back invalid. Could the implanon be interfering with the results?