when you go to your hearing what you must get accross is how these conditions or illnesses limit your ability to work. reciting a list of conditions is not going to achieve what you need to achieve. that may be why your application was turned down 2x in the first place. you must state what you are limited in doing, sitting, standing, bending, kneeling, walking, climbing, carrying etc. also the effects of medication and pain itself that limit you such as lack of concentration, which causes problems such as not understanding instructions for example or forgetting to do things, fatigue, dizzyness whatever the case is. the way that your conditions affect your ability to work is what they are looking to find out. look the judge right in the eye while you are answering his/her questions. stay on topic with your answers and answer the question asked.
dont get too dressed up or too much makeup. look the way you do on a normal day for you.

good luck. dont worry about being a little nervous, everybody is.