Maybe be due to poly cystic ovarian disease...it can occur in women who have diabetes or thyroid problems. It is also common in women with high levels of a protein called prolactin in their blood...it can be the side effects of certain drugs like oral contraceptives,antipsychotics,antiepileptics...Try to reduce the weight and maintain your BMI in between 19 to 24. Do regular exercise to maintain the weight. Try to avoid worries as they will further increase the hormonal imbalance. Once ovulation occurs plan intercourse during that period which will increase the chances of fertilization. In dietary modifications, You should decrease carbohydrate intake, take foods made-up of whole grains like whole wheat bread, Decrease fat intake and increase protein content. Take high fiber diet, fruits, vegetables but avoid starchy vegetables like potatoes. Take plenty of water avoid sugar drinks...Consult nearest gynecologists for clinical examination they will do the needful.