hi i had gone through your query and understand your concerns. i would come up with the possibility of ORTHOSTATIC HYPOTENSION
may be the cause for your sufferings.
-is not a disease or a complaint from an individual; it is an abnormal change in blood pressure and heart rate
associated with an illness.
i would suggest you taking Homeopathic
medicines gives safe and permanent cure for your complaints
consult your local homeopathic physician for correct diagnosis of the case and remedy to fit your complaints
I hope this is helpful for you, thank you