Aww, I'm sorry this is a difficult time for you in some of your friendships. Major life changes always have an adjustment period and I'm sure you'll find the perfect way to deal with this in time.
Sometimes friendships are just difficult, but if you are willing to work, it will be worth it in the end! *hugs*
I hope you have fun at your friend's dinner even if you can't eat. At least you get to enjoy her company.