young but not too young...

Hey guys I look stuff up on the internet wayyyy too much. So instead of that I thought I would ask you! So I missed like 3 days of birth control pills so I knew I needed to wait and get a new pack. I thought I was supposed to wait to start again when it was time to get the new pack. Was I? Anyways this would have been my period week (yesterday through the 13th) so should I wait and get it when my next period comes or.... just start it the 13th? And also me and my boyfriend have been having sex and not using protection. Can I get pregnant right away? And how will I know if I am if I'm on the pill and it changes my periods...