I understand that feeling. I have a career that can require long hours for extended periods of time, add a husband with the same career and hours and a family on top of that, and there can be a lot of stress. I tend to use my vacations as goals to keep me going. If I had to cancel, I know I would be very upset and downhearted. Try to keep your spirits up. Can you plan a much shorter vacation, like a weekend getaway, somewhere else pretty soon? I know it's not Disney, but it might help.
I keep telling myself this. We have a trip for a friend's wedding to San Francisco and a trip to Germany before Christmas. I am very excited to go, but all I keep thinking about is that our last trip to Disney was in March and we don't plan on going back until June. I have been listening to Mouse World Radio a lot when i start to feel sad or stressed; it helps some envisioning myself walking down Main Street at the Magic Kingdom. I think you have been very patient waiting 8 years, and I think you have the strength to continue the wait. It will give you even more time to plan and dream. When it comes, it will be awesome. Good luck with everything.