Need help

I had my daughter January 13. Started birth control February 19. Got a period from February 20 to March 7. Started having unprotected sex February 27. I'm 4 days into the last week is my birth control the "placebo" week and haven't gotten my period, just some spotting from pink to red to brown and mild cramping from time to time. Any thoughts on if it's my period coming, just pushing late because I gave birth just two months ago maybe my hormones are still out of whack? Please, any input is helpful. Thank you! :)