I am switching from Caziant birth control and have been on it for five years. I took all of the pills and now I am switching to my new birth control I am on, Tri Sprintec. I took the Sunday pill, and I want to know if I am protected or need a back up form of birth control. I read online that I am safe and do not need one, but I want to know for sure because I have also read that the birth control takes a month to kick in, but also 7 days. I am confused. I have been on a different birth control for years and things have been fine, but I switched due to money issues and wanted an easier pill.