31 f with no children. I have been taking Errin mini pill for approximately 9 months and have never missed a pill nor have I taken one late. ( I have been on hormonal birth control for 15 years) We always use a condom as well. My period is now five days late, and although I have had irregular periods on Errin, as of late they have been like clock work. I have also taken two tests ( after three days late) and both were negative. Any advice as to what may be causing the change? Pregnancy seems highly unlikely?