More than each new job makes me nervous, each new mystery I can't explain makes me nervous!!! Did I miss something small and stupid? Is this a whole new bug we haven't seen? What changed?

I figure that being nervous means that I care enough to not bugger it up and that counts. It would be easier to not give a damn, then I could be calm all day every day.

I've learned to live with it as part of the job. One thing to not do, however, is worry about what might go wrong overnight or while you are away on vacation. that's the kind of nervous that can eat you and is not healthy.

You're in good company, I didn't go to school for this, I rather fell into it a couple decades ago. Once you accept that you will never know and master everything, you'll be fine. Already being someone that can figure things out for themselves and uncover new resources to assist you in that endeavor, you are an excellent candidate for geekhood.