Is my period to early?


I recently got my birth control removed (about 3 months ago), it was the implant that goes in your arm and since then my periods have been trying to get back to normal. On the birth control I didn't have any periods for 3 years but of course spotting through out. I had my first period on the 6th of June and my 2nd on the 28th of July and my next period shouldn't be until around the 25th of this month but I just got it today. Should I be concerned? Also I was having really dark discharge yesterday and earlier today before my period started. Like really dark, almost brown pretty much. Ideas?