I've worked for big companies in my industry my entire career since 1989.
I've always conducted myself as if my actions would affect my employment - that is, I acted as if it were my company, going above and beyond of "just doing my job".
A few years ago I realized my job was affecting my sleep patterns and ultimately my health.
And ultimately realizing that MY health wasn't worth my job, I made a transition.
Now I am satisfied to do my job within my zone and not sweat the "big picture". I can only do so much and can reach fulfillment in doing that part. The stockholders will realize the rest.
I will do my part as well as I can, to the fullest part. Whether or not the mission is accomplished is not ultimately up to me but to the organization that I work for. Ultimately it's up to them and the resources they have provided.
Meanwhile, I do the best I can do and not sweat the rest.
I've worked for everything from $100m family owned to various Fortune 500s and I found one constant. I realized I can't control 99%+ of what will happen.
I try and remember my father's advice, "Give them their money's worth". After that, I try and not sweat it. It's not on me. Gets easier as life goes on.