Am I Worried for no reason?

Okay, I'm on birth control and I have the implant in my arm. It last for 3 years and on April 11, 2015 my 3 years will be up. When I first got the implant I had a light period for about 2 weeks. It stopped for a week and came back again for another 2 week. After that my period completely stopped for about 2 years. They told me this could happen and it was normal so I thought nothing of it. A couple of months ago I got my period regularly but always around different times of the month. My last period was early September and I'm worried since in a few months my BC will expire if it's wearing off? Is that possible? Lol but I'm freaking out about my irregular periods and now my boyfriend thinks I'm pregnant which makes me even more nervous. Has anyone else had this problem or something similar with  their BC? Or am I just freaking out for no reason?