Period and Birth control

I got the nexplanon implant birth control a while ago and everything was fine for two weeks or so, then I started my period and now I've been on it for about 4 weeks. Is this normal?? Because it sucks. I'm going to pick up my boyfriend and watch him graduate from AIT training in about 2 weeks and I am really hoping to be off my period by then if you know what I mean. Any suggestions?