You need to observe yourself objectively as you see yourself becoming stressed...watch how your world begins to unravel and pay particular close attention to your motivations--they are a key element.
The ISTJ deals with stress by attempting to exercise great control over everyone and everything around them. They take micro managing to a whole new level. At this point they are exacting, negative, and critical. The classic "no one can do anything right" and "I am surrounded by fools and incompetents" type individual. Often this will lead to others avoiding them and abandoning them and any projects that they may be working on as a group. This in turn leads to a feeling of being abandoned in the ISTJ, which gives place to indignation and anger, and a feeling of "I will do this just to show them." Of course, eventually this house of cards topples and the ISTJ can no longer keep up with the demands of the project so tasks begin to fall through the cracks and things are left undone, and people begin to notice that the usually dependable ISTJ is becoming a flake. So they become like an ENFP that might flit from topic to topic or issue to issue, dropping people and missing appointments along the way. The difference is that the ENFP is truly trying to get it all done and doesn't intend to drop anything, and is loving and has the best intentions--also they see the possibilities in every situation. However, the ISTJ is morose, sullen, and taciturn, seeing only negative outcomes and predicting failure at every turn. They often will know that they are dropping people, but will become flippant about it.
We can be quite neurotic if we truly are depressed.
