You deserve a break: and today just might be the perfect day for it. Any deadlines you have right now can wait, and there are not going to be any fires breaking out anytime soon. If you can, try to stay close to home: work from home if you can. You need to be in a place where you can totally relax and feel free to be yourself, without having to put on a game face or kiss up to the big boss. If you just can't get away today, then at least schedule something within the next week.