Any drills that can help with these weaknesses in my pool game?

With the exception of the break, don't use your full body. A good drill is learn how to use follow to make a leave. Forget about combinations. They're a waste of time because the opportunity rarely presents itself. I'd say practice bank shots both with the cue ball and the object ball, because you might have to use them. Also practice hidden ball shots and leaving your opponent hidden. Remember that the follow shot is more important and reliable than a draw or fancy English shot.

take a breath, visualize the shot, then take the shot