What Causes Excessive Vaginal Bleeding While On Birth Control Pills?

Hi. I missed 3 birth control pills in a row due to having surgery done on my knee and I was unable to keep anything down (frequent vomiting). I then started bleeding. I figured if I take 2 pills on my first day getting back to my pack, then continue with taking 1/day, it would stop bleeding and get back to normal. However, I ve been bleeding steadily with painful cramps for 7 days and I start my regular period in 2 days. Should I be worried? Should I stop taking birth control until I stop bleeding and then restart with a new pack?