Suggest Treatment For Tendency To Faint After Sustaining Injuries

I have the tendency to faint at specific times such as when hitting a joint (knee,elbow,wrist) and have fainted when I bumped my nose on someone's head and bleeded, when fell down the stairs and hit hard my tailbone and each time I have a virus and vomit or have diarrhea..Im not anemic, Im very fit and follow a holistic way of life.
Thank you.