copper iud

so my period according to this app is about a week late. i have the copper iud and ive had it for 4 months now. my last 2 periods were supper long and heavy and about 2 weeks appart... i guess what i am trying to ask is if i should call my doctor and see if this is normal? and who has had a copper iud pregnancy? and should i be worried? i have a 9 month old to btw. fist time mom and first time iud user..