period while pregnant?

I just had my period but it lasted a whole day and the next day was nothing but brown blood. today is nothing most of the day then some pink blood then now nothing!. I know it is most likely just a weird period but still hopeful. lol. but now I'm having pain in my right armpit that goes into the side of my boob. it feels like razor burn but have not shaved recently. just wondering if anybody has had there period and end up pregnant.