Weird Period

I was wondering if any of you ladies have experienced this.

My period was suppose to start on the 11th of September.

On September 8th I started having some brown spotting. (what it would look like at the end of your period) I did that until Sunday, September 10th. Then on the 10th I started my actual period. (It was super heavy. Like changing tampon every hour to two hours. And I had to wear a pad as well)

Well, that lasted until the 12th of September. (Three days) My periods usually last five days.

It's just had me concerned ever since. I have an appointment with my doctor next week.

Also, last month my period only lasted four days. (As I said before they usually last five days)

I did stop taking birth control back at the start of July. Not sure if that's the cause. I had only been on the birth control for about 6 months.