I'm not really down with the whole mini-pill thing, but the 'real' pill is only effective if you take it consistently - you can stop start when you feel the need. So purely based on that, I would say that perhaps it hasn't been effectively working, so I would go from a perspective of you not taking it at all.
I would do a pg test, then deal from there, and resume taking it daily (if that is how the mini pill works).