I have been on the pill for almost a year and I haven't missed a pill for this entire 28 day period (or the one before). However I took antibiotics during the second week of hormones which gave me a bit of breakthrough bleeding the first 3 days I was on them probably because my hormone levels went down from the meds. I finished antibiotics right before the 1st pill of the third week and took them all. I had sex on the 6th day of the 3rd hormone week ( I didn't have sex at all during this pill cycle till this day) but I used a condom and it never slipped off completely but slipped halfway down a few times. Now is my 3rd day on the placebo pill and I haven't gotten my period yet. Yesterday I had a little bit of spotting for maybe 2 hours but I don't know if that was my period or not because it usually lasts for 4 days. How possible is it that I'm pregnant?