I suppose we get excited and/or afraid, and our thought-engine races "pedal-to-the-metal". In the process of speeding forward, our thoughts race so fast towards a conclusion that we don't even realize that in the process we've become irrational. We've put so much trust in our thoughts, and are convinced that all of our thoughts are rational, even the rapid ones. By the end of that stream of rapid-fire thoughts, we might not even remember the chain of reasoning, yet somehow we've fully convinced ourselves beyond all doubt that we know the outcome is certain before anything has even happened! That is anxiety, a fear of the future.

To the average person a situation like the one you mentioned would probably be just an unpleasant phone call and a bad day, or an unfortunate turn of events in an otherwise okay life. On the other hand, folks like us often twist a simple fact or two into an epic fantasy involving agonizing verbal abuse, emotional torture, certain death, oblivion, and Armageddon. Somewhere in there we made a huge leap of faith in reasoning, and this caused us to go off an emotional & spiritual cliff.

Somehow, I suppose we have to slow down our thoughts/reasoning, or not trust so much in the validity of every racing thought, and retrace our steps if needed to see where the rational thoughts turned to irrational ones.

We can identify so closely with a job that it feels like it is our whole life (even though it isn't, and to be healthy we shouldn't let it be). But even supposing for a moment that somehow it is our "whole life" in that moment, realistically we ought to concede that it won't be that way forever. I suppose we forget this because our view of time has become distorted in that moment. Realistically, the world does allows for change. The same "change" that potentially allows things to get worse, also potentially allows things to get better. Potential is not one-sided. It's easy for us to get carried away with extreme thoughts and slam the door shut on future/possibility.

Fortunately, the intelligence necessary to think one's-self into anxiety or depression is also the intelligence capable of realizing that we don't have to slam that door shut if we choose not to.