iud period problems ????

taylor
so I've used this app for awhile but I've never posted anything. 
I got an iud last year this month and everything's been fine. my period regulated and it's been awesome but my last period lasted 6 days. stopped for 2-3 and then started again for two more days. then I was supposed to get my period on Saturday and it never came till yesterday. it lasted less then half the day and now it's gone. I don't know what to do or what's going on. has anyone had these problems before ?