I'm terrible in the oral test

Hi friends...

I have a big problem.

I'm doing a english course. I'm good in the composition, use of english and listening, but I'm terrible in the oral test. When I see the teacher, I forget everything what I know. I studying english grammar, I practice the listening, Everyday I access this site, but I can't... Someday the oral test kills me.

What Should I do? Can Anyone give me a advice?

[ Sorry! If I made some mistake... But I'm still learning ]