AF and Antibiotics

My hubby and I had been TTC during my fertile window, then right after the window I ended up with a bad respiratory infection and I got put on antibiotics from the clinic. I was on them for ten days. My AF was supposed to arrive Thurs Nov 13, but I was still on antibiotics until then. Now it's Monday Nov 17, AF is five days late and I still don't have any signs it's coming. I took a pregnancy test on Sunday but that came back BFN. I read online that antibiotics can delay your AF. Then I started noticing that my CM was indicating that I'm ovulating? Am I going to miss AF altogether this month? Has anyone else had a similar experience?