Gosh I think if it was my first big case I too would be stressed, especially a murder trial ! Some anxiety is normal, and it sounds perfectly natural that you should feel anxious about something thats so important to you. When I'm stressed at work over a case, and it just whizzes round in my head I generally try to escape for a while just to get some perspective, a weekend away, a night out, a relaxing gentle walk with my dogs, or a nice bath and good film, just some 'me ' time. Try to make sure you get some good sleep. I'm sure you'll cope, its the thinking about doing it thats worse than the actual doing it. Good luck