A bit worried

I got my Mirena IUD inserted on the 13th of November. I had terrible pains straight after insertion but the cramps did settle down the day after. I've had light spotting since the day of insertion. However my period came 2 weeks early on the 19th of November and hasn't stopped since. Every time I think it's stopping it comes in massive gushes then stops again for a few hours. After two weeks of continuous cycle days, i'm growing quite conserned about this level of bleeding and Wether it's going to end up making me anemic or even generally run down. Does anyone have any advice on this?