About 1 month ago I was on an antibotic. The day after I was done with the antibiotic my husband and I had sex. I was taking my BC at the time, and had my period the week of my antibiotic. I know an antibiotic can cancel out BC. About 1 week later I was experiencing light bright red spotting for about 2 days. I have felt fine for the last 3 weeks. I am now almost 2 days late with my period, my nipples are super sensitive to the touch, and I have been feeling like I am car sick since last night. I took a pregnancy test today and it was negative. I have recently started school and went off of my pill this month. Could this be pregnancy? I'm so confused.