Why do I get lightheaded and a weak/numbing feeling in my body when seeing or talking about blood?

For as long as I can remember I can't handle blood. To be honest I have a hard time saying the word. My mom has it and my gma does too. I don't just get lightheaded though, my legs, arms and fingers will tingle and get kinda numb. And most of the time, start crying. I'm an adult now but I feel so dumb having these panic attacks just because someone is showing me vain in their leg or has to take my paulse. How can I deal with this!?