R.C.
I don't really have any advice. I continued to have my period while on Mirena for 2 years. My periods on Mirena were 4-7 days and very light. My periods since removing the Mirena are 4-7 days and much heavier flow. I don't think what you are experiencing is that abnormal. If you are overly concerned you may need to talk to you OB some more.