period whilst on pill

Jessica
So I've been on the microgynon pill for over 2 years now, and suddenly all of a sudden I'm having bleeds in between my periods. It's only happened twice so far, but starting to worry if the pill is actually working?!  I would of had my bleed for the month then would start taking the pill again and 5/6 days of taking the pill I would suddenly be bleeding again. It wouldn't be just a bit of spotting though, I'm bleeding as much as I would half way through my period. What's happening? I'm sexually active with my partner and it's now putting stress on us both because we don't know what's happening? Please help