Thanks for your query.
First, i would like to mention that you have lost lot of weight, too quickly, Ideally weight reduction, has to be done in a prolonged period of time. Sudden weight loss
leads to weakness along with vitamins and minerals
) and low blood pressure both lead to weakness, shaky hands along with black out while standing up.
may have developed due to calcium deficiency/D3 deficiency.
I would recommend you to visit your physician for the following:
-complete blood count
for determining Hb and iron deficiency
-serum calcium levels
-vit D3 estimation
Meanwhile, eat fresh fruits especially one high in iron content ex: apples, green leafy vegetables (spinach), pulses, eggs, milk and milk products(to counteract calcium deficiency).