If it occurred slightly before your period, it could be indicating your period or of you had sex, some uterus movement made that blood come out (or something like that).
Although it is true that implantation bleeding occurs about one week before your period, if you have been taking bc pills regularly and on time, the chances of pregnancy are actually minimal.
You can take home pregnancy test to make sure but I honestly doubt you are pregnant.
Yeah, what the last person said: brown vaginal discharge is a sign of old blood, and that can be present in your discharge for quite a few different reasons, most of which are nothing to worry about. It can be a sign of pregnancy, since some women have an implantation bleeding, but many women also get it towards the ends of the periods anyway, or even right before. You're on the pill too, which technically means you don't even have "real" periods; the bleeding's just a result of the ingredients in the pill designed to make things look more like a normal menstrual cycle.
I am 18 years old i had most of the promblems you females are having down to the itching,drak period,coming on my menstrual period two months later. I went to the doctor every two months they told me that nothing was wrong. I ask them to check for cancer never had it,the itching i had didn't last that long my doctor said it can come from the type of pads i wear to remine you i dont like tampons dont feel right to me.all laughs, thought i had a infection never had it,I took a pregnancy test i wast'n but, the doctor did said i was drinking lack of milk, and water that infected my blood.when i start having sex that's when the dark period came i ask my doctor why do i have brown dark colorish blood? he said it came from old blood that's was in my body for a minute that was normal. OMG the moods i be feeling my family think am crazy i be happy one minute mad the next my body temperature chance very fast to cold to any type of wearther you can name but when it heats up i dont went nobody touching me talking to me or loud around me thats just me as a women of a kind and the experience that i have receive. All i can say to you beautiful woman out there when you see anything that dont look normal to you get checked out , and if you having sex or thinking about doing it always rap it up i rather be safe than sorry treat your health like you would treat a million dollar car or a house.we can't live without health/wealth. and one more thing aids dont have my name or your name on it.protection first
sincerely kim
thank you