Why when i excercise my hands and feet , even my penis feels cold , like the blood rushes awsy from them?

See details: Blood is shunted to the muscles that are being exercised and away from those that are not. As for your penis, your have to figure that one out.

You are correct: Depending on external factors such as temperature and other environmental conditions, the thermoregulatory system of the body will seek to achieve a balance between the maintenance of the body's core temperature and the release of perspiration to cool the body. It does so by varying the amount of blood flow to all extremities, muscles, skin, and vital organs which likely explains your sensations.