Should I be worried regarding irregular bleeding with Noriday?

I have been on Noriday for over a year now. For the first three months I had the usual irregular bleeding as expected but then my periods stopped for 8 months (which was fab). I've now started having irregular bleeds every two weeks. I am taking the pill at the right time and everything is as it should be. My doctor wasn't overly helpful. Is it time for a new pill?