Tension is my enemy - suggestions?

Tension is my enemy - suggestions? So, my stutter is that I hold my breath, mainly at the beginning of a statement. Once I get going, I'm fine. When I relax and not think about my speech, I'm good. But, I can't help but think about my speech, that bring on tension in my chest, and I hold my breath. It's terrible. Any suggestions on how to keep the tension down and just F'in relax?? Many, many thanks.