Hi welcome to Health care magic forum. As you describe you are getting hypotension
when you are doing physical exertion, it appears that you are severely anaemic, or there is some thing wrong in your heart as aortic stenosis
or some thing like that.
I advise you to consult a physician for diagnosis and treatment. you may need to have E.C.G., ECHOCARDIOGRAM
, T.M.T,D.C, Hb etc, for confermation.
Besides i advise you to follow some diet recommendations as take more of green leafy vegetables, pulses, sprouts, milk, fruits, juices, egg, meat,and sea foods, to provide you with iron, proteins
, for building up blood and general health.
Wishing for a quick recovery and thanks for calling Health care magic forum.