hi there..im only going from personal experience..but i had old blood and it was later to be found i had miscarried...im not saying this has happened whatsoever to you...just from my own experience...
Hi there and welcome to the forum. Well, brown discharge is old blood usually. With the stopping of your hormonal birth control and taking plan b, you've had lots of things shifting your hormones lately. This could be the reason for the late period and odd bleeding pattern as in brown discharge. I'd give it a bit more time to see if it evens out and if you continue to have difficulty, go see your doctor. If you are having to use plan b, perhaps it wasn't a good time to go off birth control. Make sure you use a reliable method if pregnancy isn't desired. good luck