Am I the only one?

Am I the only one that gets their period for 3 weeks+? 
I use to have 2 days off a year from my period. It was really heavy (still is) extremely painful. It would put me in hospital. But since getting the rod in its gone to 3 weeks sometime 3.5 weeks still really painful and heavy. But please tell me I'm not the only one? Doctors can't figure out what's wrong with me... If I'm not the only one please I need ideas on how to help. I'm only 19 and not ready for kids.