IUD periods

I’ve had my mirena iud for almost a year now. I have had light periods for the first couple months with it but recently they have been worse. Before I got the mirena my periods were moderate but not heavy and I never had any cramping. Lately the cramping and pain is terrible when the period comes. It’s heavy and dark red. I had my period from January 28th until February 28th, yes a whole month. I called the doctor and they said it’s normal until my body gets use to the IUD. I explained how heavy the flow was and that the cramping was bad. Again they assured me that this is normal. My period finally stopped and I was very thankful but boy was I wrong. Not even a week and a half later it was back. Heavy, painful and red. Losing this much blood can’t be good for me....So my question is, Should I get an opinion from another OB/GYN or do I ride this out?

Have any of you ladies had any issues like this?

My main concern is my health. Any insight or opinions would be great.

Thank you.