What Causes Dark-brownish Spotting?

I'd like to know what it means to have a dark-brownish colored spottiness. It doesn't feel a pad and mostly rubs off on tissue paper. At times there is a little that falls into the toilet when I urinate. I took my last ortho evra patch off on October 29 and had my cycle November 1st. I haven't had one since. December 12 is when the spotting started; in the morning. During my last 4 week patch cycle I put one on Sunday October 2nd and didn't change it until Wedneday October 12th. I changed that one on Sunday October 16th and changed the next one October 23rd; adding an extra one to make up for the one I changed late. I took that one off on Saturday October 29; a day early.