Spotting before period?

My period is due any day now and my face is breaking out so I'm assuming is approaching quickly. (What a lovely way to find out, with more pimples! Yay me.) anyways, I always tend to bleed before my period. In other words, I know it's coming because when I wipe, there will be brown on the toilet paper. Then today, I just went to the bath room again, and I wiped and there was even a little more brown. I've been worried that I may be pregnant however I took a pregnancy test and they both came out negative. So, this wouldn't be implantation bleeding, right? Especially since this happens often. I also stuck the toilet paper up a little further and there seems to be more dark red and brown blood waiting to come out. Is this a problem that this happens so often? Or is it normal...