Infertility Question

I completed my 2nd round of Femara during the first week of October. I ovulated on my own October 6th. I was one day late when I went into my doctors to take both a urine and blood test to determine if I was pregnant. They both came back negative. I'm currently three days late with no sign of a period starting. Is a delayed cycle common when taking a fertility drug? When should I test again?