Irregular periods after microgynon help!!

My husband and I are trying to conceive and I stopped taking microgynon after 10 years of continuous use in October. I then had a 56 day cycle and had af at Christmas. I'm now on day 39 of the next cycle and still no af. I have tested and always BFN. Doctors don't want to know as they just say it can take years for periods to regulate after the pill but it's so frustrating when TTC! I wish I'd known to stop my pill a year ago! I suppose my question is how can I tell if I'm ovulating and when? And has anyone else with this problem gone on to have children as I'm worried my pill may have been masking fertility issues! (I'm 27)