Hitting a golf ball is much like throwing a baseball or football, both of which make use of the entire body. I recently heard Doug Flutie, quarterback of the Buffalo Bills, explain that though he was smaller than all other NFL quarterbacks, he generates tremendous throwing power from his legs. The best advice I have heard on getting power out of the golf swing is the metaphor of swinging an ax to cut down a tree or chop wood. In thinking about actually swing an ax, it is obvious that power needs to come from the shoulders and legs, not wrists. I'm referring to the mental part of the game here.
Golf is difficult.
It wouldn't be enjoyable if it were easy. Don't expect overnight success. Avoid getting emotional. Your swing will not be improved with anger fits. Instead, calm down and think.