I think the best thing for you to do is sit down and have a very candid talk with her. Not so much cause you were expecting the bridal shower etc but because you would like her to know that this role of MOH (the person who has the bride's back and is there to think up of everything the bride can't, the shoulder to lean on, cry on and rejoice with, the person who come wedding day makes you look and feel your best with words of encouragement and support) is important to you and you would like to know in advance whether she will be able to attend. I had picked out two MOHs and neither can attend (one is pregnant with due date a week after my wedding and the other is having serious problems with the IRS). I didn't choose anyone else after that, I just have my two BMs, but I get where you are coming from. Talking it out and letting her know how you feel is the best thing to do. She may be so pre-occupied with the stress of her new job she may not have realized that her enthusiasm is gone.