Period stop after a yr with nexplanon?

Hello, I'm 23 and got my Nexplanon put in on Febuary 17th 2014. I had weird long spotting/periods but always got a period around the same time each month. Except now it's been a month and a half without any period and no sign of it coming. I've taken test after test and they are all negative, whew.. But I also had two infections in febuary and took two rounds of antibiotics. So did anyone else stop there period all together after a year or is it possible I could be pregnant?