Feeling stuck and going nowhere

I know there isn't much room for advancement in libraries, but how do I get over the disappoint of this.  I've been at my library for almost 9 years (3 months away from that accomplishment) and I've just been struck by the fact that until/unless my director retires, I have no room for advancement at all.  I usually like what I do, but sometimes I'm sick of having to cover for everyone at work and always being that go to guy that everyone relies on.  It's a great feeling to know I'm needed, but not so great realizing just how much I'm needed, and it would do good for certain employees to stop relying on me so much.  What am I going to do?  I've gone so far as to seek employment in other fields just for a change.