When I was admitted to hospital they gave me a very small dose of xanax and it did nothing. I advised them that I normally took a larger dose of a benzo as per my prescription from my p'doc.

I agree our brains can become very tolerant to this medication. It doesn't have to hit you in order for it to work. But it would be good it you found it was helpful. If that is not the case please check back in with your doctor and have a chat with them about possible alternatives.