thanks for sharing your problem.
first of all i would like to know your usual BP and how low it goes? Because Low BP
is a rare problem and mostly the cause of symptoms lie somewhere else. even if you are really having low BP, your cardiologist and endocrinologist
should examine you for the possible cause.
You must get your body iron levels checked before iron supplementation can be advised to you. one must sleep for at least 8 hours a day. Feeling of chronic fatigue
, thirsty, drowsy etc can be because of variety of features and let your doctor examine you and advise you accordingly
Get well soon