Nexplanon side effects?

I’ve had the implant in for 5 months now and I still get periods every month as well as no symptoms or signs of impending period, but now for the past 2.5 weeks I’ve been having symptoms like bigger sore breasts sensitive nips no appetite nausea which is getting worse by the day I wake up feeling like I’m going to throw up. So what I’m wondering is is it normal for all these side effects to just happen like this out of nowhere? Could it be something else? Anyone ever experience what I’m going through?