Pre op is no big deal although you will need to write on the forms a list of medications you normally take, any allergies you have, any other ailments and any surgeries you have had in the past.
A lovely nurse will explain a bit of what will happen prior to surgery and take your weight and maybe height and give you instructions on when to have nothing to eat or drink and at what times the night before the op. She will also give you a tube of antibacterial wash to wash yourself with before you go in to surgery. Warning- take a pair of scissors in to cut the top, I twisted my cap off and it didn't come off right and the hole was so small the back crimp exploded and put soap in my eyes. Not fun.
They may also have an anaesthetist to interview you and give you an idea on what to expect on the day and see if you are allergic to any medications.
I also sat up a few hours through the nights and couldn't concentrate on a darned thing. Not even music made be feel any better. You just have to weather it I think. Time does pass and nothing bad will happen. Just have faith and hang in there.