Help conflicted about using plan b or not

Hi I started my birth control pack on a Sunday and on Monday night (my second pill of the first week) I forgot to take it. I took it on Tuesday morning right away which ended up being 13 hours overdue and took the rest of my pills normally. Yesterday, on wed the condom broke and that was after taking my 4th pill of my first week. Should I be taking plan b now? :(

Also if I do take plan b today and take my pills normally, how long should I use a backup method for? Until a week from today or since Monday when I forgot my pill