Antibiotics and Delayed period?

Me and my Husband have been TTC for 13 months... I am 3 days late right now and in the 13 months of tracking I have only ever been 1 day late on my predicted period. I have tested all three days-all negative. I have been on antibiotics for a serious bacterial infection and I am seeing on some blogs that antibiotics can delay your period... Do you think I am testing too early? Or has anyone ever had a medication delay your period? I was SO excited until I read those blogs :(