I also agree that not replying is the best way to go, but for slightly different reasons.
I don't think she is agog waiting for a reply from you. I think it's clear that she is not thinking about you very much at all. Her head is so full of Bridezilla shit - favours and menus and flowers and waxing appointments and hen nights etc - that there is no space to think about someone else's feelings.
You will not be the only person she has offended.
She will be in the grip of probably ten or fifteen severe "problems" at the moment, which to her, will be as serious and pressing as the decisions Churchill had to make during the Blitz. They will be things like:
- she wants the hairdresser to arrive at 0900 hours on the day but the hairdresser says she can't be there till 0930. The wedding is at 1400. Does she sack the hairdresser and get another one? But this hairdresser does her hair so well. Why can't the hairdresser come at 0900 just this once? Why can't the hairdresser's childminder take the children early/the hairdressers sick mother put herself on the commode/ the hairdresser's DH walk the 10 miles to work so she can have the car? Emails flying back and forth.
- her sister, a single mother with no money and support other than people coming to the wedding has just had a baby. Her older DD is bridesmaid and sister has got to be there to control the DD. Baby is not invited though. Sister is being difficult about this. Says baby is BF and she has no one to look after it for her. She needs her sister to be there! Some people!
- there is a spelling mistake on one of the menus and she wants them done again for free. But the printers say she should have proof-read them before printing. She gave them to a friend to proof-read and they obviously didn't do it properly. It's all right for the friend - they haven't been invited to the wedding so they won't have to face the embarrassment of people pointing out the mistake on the day. But she will lose face. Gaaaah! What to do?
- there is a red and yellow colour scheme. Groom and best man have suddenly out of nowhere refused to wear a red rose in their buttonhole. They say it's something to do with being from Yorkshire - she has never heard anything so stupid in her life! Yes she knows they are Yorkshiremen through and through. No they can't wear a white rose, it would ruin everything. Why can't they wear a red rose on her speshul day? Why? Why? WHY? She is considering calling off the whole wedding.
He inbox will be full of hurt and mystified messages from other people. Your email will hardly register with you.
And of course she is trying to get her hall decorated. That must be taking up a bit of time . . . 
Save the email exchange though so that when she contacts you all bright and breezy after the event because "Tidy MUST want to see all 540 photos" you can remind her. The penny will probably drop then.