Normally I have my period around every 28 days, I'm overdue by 5 days, haven't got a partner so haven't had sex. I'm a healthy 45 yr old woman, regular exercise, 5ft 1" about 8st 12lbs. The only change is that I have had to take threadworm tablets. I've taken the 2nd tablet, so I was wondering if this would cause my delay in my period? Thanks