Oh wow... I hear you! It is so hard to put on a cheerful face when you feel so horrible. What is amazing is that nobody will know that you are dying inside. That is the main problem with fibro...everyone thinks you are normal and can't see the pain.
I'm in the middle of a flare too. My kids are driving me nuts. I can't stop crying, my blood sugar is up, can barely walk. Yesterday my DD was invited to a birthday party an hour drive away. That means FOUR hours in the car. Driving her up, coming home, going to pick her up and driving home. And of course I have to put a smile on my face and take my DD shopping for gym clothes today. I just want to lay in bed and sleep.
I hope you get some rest after you get home and feel nice and refreshed tomorrow.