Question about birth control

So I just started taking my birth control on Saturday, the day I ended my period. My boyfriend and I have been having unprotected sex since the first day I started my birth control (and ended my period). I told a mutual friend about it and she told me that usually you're supposed to have PROTECTED sex for a week while you're still on your birth control. I shouldn't be ovulating anyways since I just ended my period but Now I'm freaking out. My doctor never told me that I needed to still be safe by condoms for a week. Is what my friend told me true??