... I had and it made my period come 2 weeks early. My gyno told me that the antibiotics just messed with my cycle and to switch to the 7 inactive pills while I was bleeding before going back and finishing the 10 or so active pills that I had left. I've never missed a pill and there was inly 1 time that I took it more then an hour later. She assured me that I would still be protected from pregnancy, but now this month I started a very light bleeding a week early that's lasted almost 7 days now, and my breasts are really tender. Is my body still adjusting from the antibiotics or is it possible that I'm pregnant?