My Period Lasts Up To 30 Days At A Time

My period lasts up to 30 days at a time of continual bleeding, then I will be off for a month before it starts again. I asked my doctor about any health concerns and he said that its normal and I shouldn’t worry but that he didn’t want to put me on any un-necessary education (birth control). I recently learnt that we loose eggs each cycle and i was just wondering if having my period for 20+ days will effect my chances of getting pregnant.