How does one express disappointment in a friend?

I have a very close friend who has disappointed me. All right, I’ll say it. This woman is my best friend.

We are supposed to be working on a project together that is important to me , and she seems to have lost interest. We live very far from each other and communicate by chatting online daily.

When I wish to talk about the project, recently she always has excuses not to.

I am hurt, and I am stuck. I am especially hurt today, because the house was quiet offering the opportunity to chat by video, which we haven’t done in ages. She decided to do something else, and she didn’t even explain. I only knew by seeing her posts on Facebook what she was doing: watching football.

Please, don’t advise me to find another friend. I have a lot of acquaintances, and a few are friends. This is my best friend. We have known each other over 14 years. She honestly knows all my secrets.