Just need some info before I freak out

Hi I have had my iud since October 2013 I always get my period on time that my glow app says this month I was supposed to get it 4 days ago I have been feeling some cramps nothing bad iv been hungry as ever and I have been peeing alot . Other then that nothing else has been happening no spotting me and my husband do it regularly like every day except when I'm on my period have any of you women had your periods late from the iud or could this be a pregnancy? I will be making a appointment tomorrow with my doctor but I wanted to her some of your story's about the iud I have heard it's a good birth control not to worry but then iv heard story's about women getting pregnant with the iud . Thanks for all your support that you give us women