I just finished up my last birth control pill on July 17, 2004 & I had a normal period exactly 30 days later. Figuring at thirty days, I should have started my period last Friday, but 4 days later & still nothing. I have occasional light cramping like I could start, but that's it. Would it be usual to be late this month after already having one normal period after going off the pill? The only reason I'm concerned is because last Thursday I took Tylenol Severe Allergy, & I am currently on steroid eye drops as well as antibiotic eye drops for an eye infection. I am hoping I'm just late for this month only for the reason I'm scared of what this medicine may have done if I am pregnant. I would really appreciate advice!