Your doctor needs to do a complete endocrine workup, covering all of the pituitary hormones.
You may need replacement hormones if the pituitary was damaged from the surgery and can not produce sufficient hormones.
Please do insist on being referred to an endocrinologist and having comprehensive testing done.l
It sounds like you need some routine blood work. Menopause, at your age, is unusual, but the pitutary controls reproductive hormones as well as thyroid hormones. Have you seen your doctor and requested blood work?