What's wrong with my head?

I was about to nail my declamation piece when...waaaaak...I had this mental block again. I have this everytime I stand in front of a crowd, no matter how small, and speak something. I don't know what's wrong with my head. Or is it even my head? Or my mouth? Do I have a defect on something? Am I abnormal?

*nothing more to say...

...mental block again????