usually before i throw a pitch or bat i get so nervous and i mess up is there any way that i can relieve myself so idon’t messs up next time

Take a deep breath and thrust yourself. Also try to imagine you hitting the ball or getting the strike. And don’t think too much, just do what you normally do.

Develop a routine for preparing after stepping up to the plate or for throwing a pitch and stick to it absolutely rigidly. That will help to keep you from thinking (and getting nervous).

In my experience, visualizing also works well when it comes to pitching and to a lesser degree when it comes to hitting.