Mommy period question

FTM of a beautiful almost 5 month baby girl and I have an issue... after I got the ok I went on birth control for the first time ever. And I expected some spotting in between periods... but I'm having full on periods with a week break! Ex. Week one- nothing week two - period. Week three - nothing week four - period and so on. Is the the BC? It's extremely frustrating and quite frankly I can't afford pads every other week!

Anyone else dealing with something simular or should I call the doc?