Hi, I'm 20 years old, 145 lbs, 5'10". Since I have been about 12 I have suffered from cold and white or purplish hands/feet. It generally occurs when it's cold out but also when I'm sitting around and inactive for a long stretch of time. Also I get red, hot hands when it's very hot outside and I let my hands hang down, but if I lift them into the air my veins stop bulging out and my hands return to their normal color. Know what this could be?