Extended period....

So I stopped taking my birth control Oct. 27 before that, my period had ran Oct 13-19, then after I stopped my birth control I got another one Oct 30-Nov 5. My next period started Nov 29. Now I know when you stop birth control your body can do weird things. But when I was on the pill, my periods happened for 7 days. Always 7 days. When I got my period right after I stopped the pill, it ran a normal 7 days.... this period is going on day 8. What is happening??? I've been on the pill for 3 & a half years and everything has always been normal and regular.... so I'm not sure what to think.