Pregnancy or Side Effects?

I had unprotected sex about 3 months ago, I use the implanon as birth control however. I have many friends who stop getting their periods on the implanon, some of them stop immediately, some of them took up to a year to stop. When I had unprotected sex, it was around the one year mark of me getting the implanon. I now haven’t had my period for 2 months but took a pregnancy test which came back negative, is this just the implanon kicking in? Am I just being paranoid?