What Causes Delay In Periods?

Hi, I'm 38 years old . I underwent a surgery to remove a breast cyst on the 28th of last month under GA. I had antibiotics and painkillers for about a week after the surgery.my cycles are fairly regular . i have 28-32 day cycle. but its been more than a week, its delayed. should i wait or consult my gynac? one more thing, whenever I fall sick and i'm on medication, it does get dealyed? will the GA cause my delay?