Shortness of Breath and Other Problems.

Short of breath on minimal physical activity (walking up or down stairs). Hypotensive on standing. Fatigued most of the day, even though well rested. Discomfort in upper chest sometimes, attention will be brought to it because of a big heave that my heart will make. Along this heave there will be a chest pain although it fades away, leaving me scared. Recently moody - was happy then got really violent with my sibling without my control. A couple times upon standing I have partially seized - partially meaning I was awake when a numbness spread throughout my body and I called out for my mom repeatedly as my arms started convulsing and repeatedly hitting the wall. That has happened several times. Heart rate while standing will rise up to constant 140+. Have vomited from the nausea felt with the chest fluttering and pain episodes. Have been to doctors before, diagnosed malnutrition and sent me off - but I am not, I eat every meal of the day. Sometimes I am actually very hungry (like now).