Sorry to here that, i hope it all goes well.
I wish i could offer some advise,
All i can suggest is do something that you find relaxing.
Reminds me of a saying my father had, he said "Only worry about things you can solve and once solved theres no reason to worry"
In other words dont worry about it and you should be ok.
I know that may seem like a stupid idea but trust me it does work.
Good luck for tomorrow.