Is this something I should be concerned about? Maybe (I know you're not doc!
Question: Is this something I should be concerned about? Maybe (I know you're not doctors) explain what it may be?
Answers:
It sounds like you are shedding extra blood this month. Sometimes the uterous doesn't get rid of the excess every month, and so you get months like this from time to time. Don't worry about it, it's normal.
It's perfectly normal to experience an irregular period every once in a while. That's exactly what this sounds like. You have to remember that birth control pills are not magic, they're just hormones. Your body produces hormones of it's own naturally, and it's not uncommon for normal fluctuations to result in a simple irregular period.