Birth control pills are used to prevent pregnancy but they can be also used to treat irregular menstrual cycles. In your description, it is not clear when and for what purpose you have used birth control pills.
If you have ever used birth control pills to prevent pregnancy, you should know that after you stop taking them, you might experience a lack of period(s) called "amenorrhea", or irregular cycles for some period of time. During that period, fertility decreases. The duration of the infertile period varies in different women (usually 3-4 months but the maximum length is 2 years).
Women with irregular cycles usually don’t ovulate and that’s why they can’t conceive. Birth control pills are administered in such cases to establish regular cycles. Pills can only establish a regular cycle, but the a cycle while on birth control is still without ovulation. It is the medical practitioner's hope that a woman stops taking OCPs (oral contraceptive pills), her cycle will remain regular and that ovulation will re-establish itself spontaneously. Hormones found in contraceptive pills can alter the functional status of the axis hypothalamus-pituitary gland-ovaries to induce normal cycles (with ovulations), but not in every case. If this doesn’t help, some women seek treatment via ovulation stimulators, like clomifen.