Lack of menstrual periods is an expected temporary side effect after coming off birth control pills. It seems that your doctor gave you birth control pills to make your cycles regular. Before you started taking pills, its sounds as if your periods were too frequent (polymenorrhea) and too prolonged (menorrhagia). Your cycles/periods were irregular probably because you weren't experiencing ovulation. Lack of ovulation is due to a disturbance in the axis hypothalamus-pituitary gland-ovaries. Pills can make the cycles regular and can stop bleeding... but while taking them there will be no ovulation. It is believed that after coming of birth control pills, ovulation will establish itself again, spontaneously. If birth control pills do not help, you can consult a gynecologist and endocrinologist about your period regularity.
A bloated and painful abdomen is probably not related with your reproductive system.