What Causes Delayed Periods Along With Cramps While On Cerazette Contraceptive Pill?

I ve been on cerazette for over a year and have been having unprotected sex with my partner. I vomited on Friday after taking my pill and took another one, then the Saturday forgot it (which never happens) we had unprotected sex. I then got the morning after pill. I rarely menstruate due to my daily contraceptive pill, however have not had any bleeding since taking the morning after pill. Just some cramps similar to menstrual cramps. Is it normal to not bleed post morning after pill while on cerazette? Thank you, M.