What Is The Prolonged Period After A Miscarriage?

Hi! I have had Mirena for almost two years. I had a miscarriage two months ago, and I had my gyno check me out to make sure everything was in place/okay. Now, I'm having a problem where I've been on my period for nearly two and a half weeks. (I haven't had a period longer than three days ever since I had the Mirena placed.) Is this normal?