just want advice thanks

I have been on cetazette pill for only a week now and started my period on the Friday last week  my period should of came before Friday and today which is Sunday I had sex twice while on my period sound horrible but I heard it get rid off pains didn't us no protection so I am worried because I haven't been on the pill that long but weeks before I started the cerzette pill I was on a different pill but I had to start talking when I know when I was about to start my period.