Dissapointment

I have a friend that I have known for 24 years. 24 years! I am only 29! Needless to say, we have always been closer than close. She moved to Vegas last year, we have been missing each other big time but we keep in touch. I messaged her last week when I got my surgery date because I knew she would want to be one of the first to know. I got a message from her today that said "May 7, so I guess you aren't coming to Vegas for my 30th birthday..." (her birthday is May 10). Excuse me?!?!?!

I am so upset I don't even know what to say to her. I have not responded yet because I know I won't handle it well until I calm down, but, really, if anyone should understand my reasons and be supporting me, I would think it would be her. I guess I am just hurt and really disappointed by her actions.

Am I over-reacting here?