What Could Cause Delay In Periods?

Hi, I have a couple questions. First I ve been having a light brown discharge for a couple days now and my period doesn t come till next week. I also changed to a new birth control last month so I don t jnkw if this is a symptom. Also my gyno hasn t done a papsmear yet because I m not sexually active but my moms mom had cervical cancer and uterine cancer also and was wondering if I should be worried about this?