I am on the pill but got put on an one day antibiotic pill, Diflucan, for a yeast infection. A day after taking the pill, I had unprotected sex. Realizing that the antibiotic may cause the birth control to not work properly, I took plan B roughly 70 hours later. However, I started my sugar pills the day before I took plan b. I usually get my period 3 to 4 days into my sugar pills. I have yet to get my period but I have heard hormones in plan b can cause it to be late. Is my period delayed just until my next cycle of sugar pills since I had to start a new pack or could I be pregnant?