Weight gain and irregular periods are common signs of hormonal imbalances, such as Polycystic Ovary Syndrome (PCOS) or thyroid issues. Because treatment depends entirely on the underlying cause, you should not start any medication without a proper medical evaluation. I highly recommend consulting a gynaecologist. They will likely order blood tests to check your hormone and thyroid levels, and possibly a pelvic ultrasound. Depending on the diagnosis, they may prescribe hormonal contraceptives to regulate your cycle, metformin for insulin resistance, or thyroid hormone replacement. For now, focusing on a balanced diet and regular exercise is a safe and effective way to help manage symptoms.