There will be a flight that will be horrendous. Nothing will go right, the maneuvers will be out of their parameters, and you will bounce on the landing. It will happen, and you can get over it. It is one of the important steps of learning, so go home and relax, keep studying, and move on from there.

Doubling up on what JNB & Ninja said, study. Either go into each lesson with at least some basic understanding or you will wind up having your instructor spoon feed you every piece of information while you are being charged. If you wind up in that situation, take notes and dont just listen and nod your head, because it will waste both of your's time as well as your money.