what is going on?

I am 20 years old and have had the implant for round about a year now. My periods have always been strange, always irregular and have always had spotting. However recently, I have been having my periods for three weeks at a time. Then I will stop my period for a day or so, and then come back on my period for another week or however long it feels like it. Does anybody else have this problem? And what can I do about it?????