It sure sounds like it Hun... there are several things that can throw off a period by a few days.. stress, if you had been since recently (cold, flu etc) weight gain/loss, hormone etc.. If this is the 1st time for this to happen, I wouldn't worry about it. But if this does continue next month as well like this, I would see your doctor to rule out any infections and to check your hormone levels as well. The BCP's you are on, may not be working anymore. But at this point I wouldn't worry about it.
Hope this helps...