I am 6 4 , very skinny (150 lbs), 20 years old, and cannot gain weight no matter what I do. This is not the problem though, just a little background to it. My problem is that i always feel tired and exhausted. No matter how much sleep I get I always find myself feeling drained very soon in the day. If I drink coffee it can help me tremendously but only for a couple of hours before I come down off of it. I know it isn t that i m growing dependent on coffee because my fatigue was the reason I started drinking it. It s the only thing that seems to give me enough energy at least for a while. I have also found that if I stand up in one spot for too long I begin to feel extrenely sick to my stomach get hot, and feel like I might faint. But if i m moving/walking i m fine. It s just when I stand still in one spot. Also, my veins in my arms sink in a lot of the times creating little trenches in my arm. But other times my arms are extremely vascular and my veins protrude a lot. My heart seems to flutter at random as well. When i m laying in bed and it s quite, i notice my heartrate will randomly increase and have a few quick burst, then slows back down to a normal pace. Not only does the speed increase but the intensoty as well. I can feel my heart beat pulsing through my neck and chest like a hammer. It doesn t hurt, it s just a very hard few beats during the speed up time.