Hello Cynthia,
Welcome to ehealthforum.
If you are having periods every other month instead of every month after your childbirth, it is possible that your menstrual and hormonal cycles have got set into a definite and changed pattern.
If you are anxious to have a baby again, then you should consider discussing your pregnancy plans with your gynecologist and get hormonal tests, ultrasound scan done to confirm if hormonal levels are fine and if you are having periodic ovulation (egg release from ovary). If there are any abnormalities detected, appropriate treatment would be started to correct these and help you get pregnant.
Take care.