Any advice would be helpful?

Whenever a really attractive guy talks to me, I freak and act like a retard or a robot (disturbingly uncaring and emotion-less cuz I'm freaking out inside). Its SO embarring and stupid, and other times when I WANT to talk to a hot guy, I freak out extremely and never do it. Do you have any advice, or what I can do to help this, or words of encouragement for me and my pathetic problem?