No, you're definitely not the only one living in fear of running out of any creative originality.
I sometimes wake up in the middle of the night in a complete panic, because what if I've used up all of my good ideas? What if this is it? What if from now on, I'll just invent pointless re-hashes of old ideas, desperately striving to recapture any spark of originality?
And then I can't sleep, and am a mess the next morning, and it sucks.
But you know what the funny thing is? I keep coming up with ideas. Because I keep experiencing and learning new things, I get more and more to draw from when I need inspiration, so instead of running out, I keep getting MORE mojo.
I just wish my brain could skip the panic-in-the-middle-of-the-night part of this process.