Ladies, a question....

I missed a BC pill on Tuesday, and just started bleeding today, even though I have taken my pills every day since. Also, my belly button was bleeding the other day; when I googled symptoms, someone mentioned endometriosis. I know that is a little obscure, and probably not what's happening, but do you guys think the two could be linked? I'm going to call my doc's office tomorrow and see if I can talk to a nurse