Bleeding with IUD?😢

When will heavy bleeding stop with the IUD. I got the IUD at my 5 week postpartum appointment. At 5 weeks I stopped any kind of bleeding and spotting. As soon as I got the IUD it’s been heavy bleeding it’s first few days it was spotting, now I’ve full blown bleeding for 12 days. I’ve it over 2 weeks. I had to start taking iron supplements because I was starting feel weak. After I gave birth I became anemic and lost a lot of blood. I knew I could spot 3-6 months but I didn’t know it was be heavy bleeding.