When I'm a nervous wreck about something, it helps me to sit quietly with my fears and figure out what exactly I'm afraid of, and how exactly it would be worse than what I'm already experiencing (and handling). This gives me a sense of competency that I can handle the worst that can be thrown at me.
Then I think about what I need to keep top of mind. For example, given that you're going to mediation, what is your top priority and is it realistic and reasonable? What are your negotiables? Know yourself well before you go in and you will be fine.
Also, I don't know if this will help you, but it helps me. I think of something I was a nervous wreck about in the past, and how I don't even really think about it much anymore. Telling my kids we were splitting was horrible in the anticipation and horrible in the execution, but we all got past it and now it is history. Everything passes, time moves on. Let your mind leap over this for a little break in the anxiety, to imagine it being in the past...which will be soon.
Adinva 51, S20, S18 M24 total 6/15/11-12/1/12 From IDLY to H moving out 9/15/15-3/7/17 From negotiating SA to final D at age 50 5/8/17-now: New relationship with an old friend __ Happiness is a warm puppy.