Simply put, in the amount you are talking about, it is all in your head. I donate blood all the time, never feel anything but ready to get out of there and on with my day. I have watched minor surgery on my own body (under a local) with no ill effects. My ex, on the other hand, would almost faint at the sight of blood, anyones blood. Don't know why some people are different, they just are. Don't know if there is any way to change it either...