I haven't been very good at taking my birth control this month (I'm usually very diligent about it, but I messed up this month). I have a Sunday start and took the entire first week of pills. I missed Thursday of the second week, and Sunday and Tuesday of the third week. I then started bleeding on Wednesday, but still took that pill late in the day, took Thursday, but skipped Friday and Saturday since I was still bleeding and decided to just let my period come early. I usually don't get my period until Wednesday, 4th day of placebo, and it ends 1st or 2nd day back on the pill. It's Monday of the week I should be on the placebo and I've really started to flow now (like a real period, not spotty breakthrough bleeding as the few days prior). Do I just let my period pan out as regularly, then start a new pack on Sunday as I usually would?
Also, how long would I have to use a backup method to prevent pregnancy?

Thanks in advance.