I have a question regarding my menstrual cycle. It was due yesterday and it's not here yet, only very, very light spotting. I am usually quite regular as I am on birth control pills and have been for about 15 years. I had sex with my bf on Oct 8 during the second week of my pack. I never missed a pill and we used a condom; no contact without one. I have been on a heavy dose of Biaxin for the last 8 days and am wondering if this could be the cause for my delay in menstruation. I had breast tenderness and swelling last week and have had some other mold PMS symptoms but no period yet. I know it's only a day late but I am a little worried. Know I shouldn't be probably, but I need a little guidance. Thoughts on this scenario??