I Stared Spotting Three Days Ago. That Was About Three

I stared spotting three days ago. That was about three or four days before I was suppose to start. The spotting started off light pink and sometimes light brown. The spotting was very light and sometimes none at all unless I whipped. I had a very small cramp the first day and stopped. This afternoon it got a little heavier with small cramping. The blood is darker, but still has a brown color to it. My periods are very regular. When they start, they are always start head one bright red and heavy. I am so confused. I know I have to wait a little bit to take a test, but it's bothering me because my period never acts like this.