I am afraid of large, big-boned females.

I have always had a fear of large, big boned females. Got in a fist fight with one when I was a kid. I kicked her ass, but she put up one hell of a fight. And her punches hurt. I am a small guy but I'm no push over. Large women terrify me. Is this normal? My wife knows this and says that she will always have my back. Men don't scare me. Do I need a shrink or what?