Super long period

So normally my period last 7 days but I'm going on 12 days. The first 5 or 6 days was browning and yucky and it stopped so I thought I was done then the next morning it was bright red and it's been like that for 6 days. I'm on birth control and wasn't taking my pills properly so I hoping that's it and it threw off my cycle? Anything else it could be? I'm a little nervous.