spotting.

I have been using the patch for over four months and I have been good a remembering my change day except for last month, after my patch free day I forgot to put my new patch on for three or four days. it has been two weeks and I should have one more week before I am supposed to get my period but today I started spotting, it is different then when I have my period and it is very little "blood" mostly when I wipe. I have only ever had this one other time when I first started the patch because my body  was getting used to it. But I am worried that because I did not have the patch on for three or four days when I should have that this may mean I am pregnant or something. Can anyone help me out? Any information on spotting would be good please and thank you.