My interaction ability

I feel that I don't interact well between even people I know.
I just don't know why, no matter how hard I try and how hard I tell myself don't be scare. But when times come I just freak out...
I can't mix well, I'm always speechless or emotionless when I meet people. Sometimes even with those that I know but not close with, especially girls...

Sometimes I ask myself, is this the effect of being in a boy school for too long or effect of something else.
Is it my self confident that is giving effect too?

Sometimes that is why I only chat through the net with people I know.
I don't speak to them face-to-face.
I just want this part of my life to change.
I pray God can help.