Is this implantation bleeding or something else? please, help.

[deannadroid]

I am 19 years old and have been on birth control for about two years now. For the most part, I am having unprotected sex. Just a few days ago, my boyfriend finished inside of me. About perhaps four days later, I started getting very bad cramps. They hurt a lot like I was getting my period but at the time the cramps started, I wasn't due for my period for another two weeks. That night and the next day, there was some blood when I wiped and some on my underwear. Very light. The cramps continued to the next day, and then the day after that the blood got heavier and I thought maybe for some reason I just got my period earlier than expected, considering I just started a new diet and exercise regimen and I know that that can have an effect on your period. But now, after about five days of cramps and blood, the blood changed to being a brown color and is very dark instead of the regular blood red it was two days before.
I don't understand what's happening.

Could it just be that I got an early period because of the change in diet and exercise? I am also incredibly stressed out but to be honest, I always am and it hasn't had an effect on my period yet but maybe this could be it?
I am now a week away from my period and I am just so confused and nervous.
Please can someone shed any light on what is happening? Should I be worried? I take my pills consistently every day and haven't had a problem at all with this pack so I hope things are alright and that I am protected.
please!!!

[Newmomma_2015]

Hmm when I was on the pill my period came basically on the same day every month. I would take a pregnancy test to ease your mind.

[cantpickaname]

That sounds like you just got your period early to me. However, if you're still concerned you can always take a pregnancy test. :)

[xojensen_]

Have you been having less or more sex than normal? My period would always change up when me and my boyfriend started having more sex than I was use too