What Causes Delayed Periods Followed By Light Menstrual Bleeding?

Hello. I am 28 yrs old and am currently 3 weeks late for my period. Yesterday I started to have VERY light bleeding and today it is still very light. Could this be my period? I have no other symptoms and usually always cramp with my very regular period. I am trying to get pregnant so could that be a possibility or does it sound like something else could be causing the late light bleeding?