You seem to be suffering from hormone imbalance
and you need to get a complete hormone evaluation to see if there is any hormone imbalance that has caused this disturbance or if the sudden weight gain has created some hormone imbalance and hence the delay. A trans-vaginal sonogram helps to see the status of the pelvic organs and excludes any cysts of the ovary. You can see the withdrawal bleed 3-7 days after completion of the hormone course, so, please wait until the period is over. Maintain a balanced weight, regular exercise and healthy diet. Once the exact cause is known, treatment becomes easy. Take care.