Please do not remove the IUD yourself and get it removed from your doctor. Although efficacy of the IUD decreases after continuously keeping it for such a time, it may cause pelvic inflammatory disorder, amenorrhea, irregular bleeding, weight gain and sometimes unwanted pregnancy.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care and please do keep me posted on how you are doing.