Are you doing a good job?
One way to approach your work: "I come in on time, even a little early. I do what the boss asks, a bit faster than she expects. I stay on time and on budget, and I'm hardworking and loyal."
The other way: "What aren't they asking me to do that I can do, learn from, make an impact, and possibly fail (yet survive)? What's not on my agenda that I can fight to put there? Who can I frighten, what can I learn, how can I go faster, what sort of legacy am I creating?"
You might very well be doing a good job. But that doesn't mean you're a linchpin, the one we'll miss. For that, you have to stop thinking about the job and start thinking about your platform, your point of view and your mission.
It's entirely possible you work somewhere that gives you no option but to merely do a job. If that's actually true, I wonder why someone with your potential would stay…
In the post-industrial revolution, the very nature of a job is outmoded. Doing a good job is no guarantee of security, advancement or delight.