Does Heavy, Sore, Irregular Periods Indicate Implanon Implant Renewal?

Hi i have the implanon implant in, its not due to be renewed untill feb 2012 but iv been experiencing some really sore and extreamly heavy and irregular periods. I spoke to my gp and she mentioned my implant might need renewed sooner. I would really like to know if their is any chance at all that i night not be covered completely by my implant?