Just throwing this out here and you may already be familiar with it but I know a lot of people who have similar feelings who wrestled with imposter syndrome.
Parts of that sound a lot like what I see in developers feeling like they aren't capable and will be fired at any time for being an "imposter" despite being totally awesome, knock it out of the park engineers.
Either way, talking about these types of things helps and if it's causing you as much stress as it sounds like see if you can find someone to talk to about it(mentor, counselor, etc).
Parts of that sound a lot like what I see in developers feeling like they aren't capable and will be fired at any time for being an "imposter" despite being totally awesome, knock it out of the park engineers.
Either way, talking about these types of things helps and if it's causing you as much stress as it sounds like see if you can find someone to talk to about it(mentor, counselor, etc).