Period after breastfeeding

My daughter weaned at 13months, I got my period back literally the next day. Since then it's been incredibly irregular, painful, and heavy. Is this normal? I have paraguard IUD and I just got back on regular birth control pills to help with how horrificly heavy they are.. but I'm still getting my period like every other week, them lasting 7-9 days! It's getting old...fast, esp after not having one for almost 2 years!