Take your vitamins and if you have just got off birth control. I would wait about 4 months before trying. Just to make sure it sticks. Just saying from my experience.
Also aince your period is irregular you won't ovulate on the same dates take an ovulation kit its just like a pregnancy test it tells you your most fertile days take the one for 28 days if you don't finish it then you can use the rest for the next month
Take folic acid. Folic acid will help regulate your periods, which will help you ovulate, and its also good for conceiving. I took folic acid for two months straight and I'm due in 3 days
you would still ovulate regularly