How to survive as a bridesmaid?

I need some words of wisdom! I'm a bridesmaid and am having a really hard time dealing with a completely unreasonable bride. It's to the point now that I don't even want to be in the wedding. I wish I could back out but it's too late and that's a terrible thing to do to a bride anyway! The wedding is this weekend. What can I do to help me to deal with her in a kind, supportive and pleasant manner without losing my sh*t? I keep trying to tell myself that she is being a bridezilla because she is stressed, she is having bridal dementia and it will all be over with soon, I just have to hang in there, right? She has demanded my presence every single day this week! I have work to do and a family to take care of so I cannot be there to be at her beck and call. I am a very hot headed person and I am so afraid that something rude will slip out on the day of the wedding. Is there anything that I can or should do to calm myself and rationalize before dealing with her for an entire day? I hope that she will be so distracted by other things that she won't have time to be a B**** to everyone....wishful thinking, I know! Anyone else had to deal with this kind of thing?