Third ventricle herniation into sella giving appearance of empty sella syndrome, due to intracranial hypertension' on my recent mri. can this be the cause of my low blood cortisol levels? what symptoms are expected from this? thank you?

Low bp, low thyroid : Empty sella syndrome can cause pituitary insufficiency with low blood pressure (dizziness, even fainting), abnormal thyroid function and changes in blood sugar. Potentially very serious. See your doctor ASAP

Empty sella syndrome: Usually pituitary function remains preserved in empty sella syndrome, but would be of value to obtain a pituitary reserve study, and a full endocrine profile in view of your complexities. Indeed, an endocrinologist would be very worthwhile.