Irregular periods, prescribed birth control pills, did not take them since trying to conceive. What else can be done?

Hi! I m 24 yrs old married woman. It s been 1 year I got married. My problem is, I have irregular period cycles before my marriage and till now (after my marriage). Before it used to be once in a two months. But, now, it s getting more than 2 months. Actually, I m originally from Nepal and it s been like 14 months, I migrated to USA. My weight is about 100lb. What can be the reason? I had consulted to a women s doctor 2-3 months ago and she suggested me to have birth-control pills . I don t have any kids now, but planning to make baby within a year from now. That s why, I denied to have pills. Do I need to do pregnancy check ?? Please, suggest me !!